Flagship Ventures Fund 2007, L.P.

SEC source: 0000899243-19-026439 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F3 · kind: On October 29, 2019, Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007") distributed to its limited partners and sole general partner, Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP"), pro rata and without consideration, 1,061,102 shares of the Issuer's common stock. Flagship Fund 2007 GP, in turn, distributed to its members, pro rata and without consideration, the 248,379 shares it received from Flagship Fund 2007. Dr. Afeyan, a manager of Flagship Fund 2007 GP, received 92,796 shares through Flagship Fund 2007 GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F3 · price: On October 29, 2019, Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007") distributed to its limited partners and sole general partner, Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP"), pro rata and without consideration, 1,061,102 shares of the Issuer's common stock. Flagship Fund 2007 GP, in turn, distributed to its members, pro rata and without consideration, the 248,379 shares it received from Flagship Fund 2007. Dr. Afeyan, a manager of Flagship Fund 2007 GP, received 92,796 shares through Flagship Fund 2007 GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F3 · balance_after: On October 29, 2019, Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007") distributed to its limited partners and sole general partner, Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP"), pro rata and without consideration, 1,061,102 shares of the Issuer's common stock. Flagship Fund 2007 GP, in turn, distributed to its members, pro rata and without consideration, the 248,379 shares it received from Flagship Fund 2007. Dr. Afeyan, a manager of Flagship Fund 2007 GP, received 92,796 shares through Flagship Fund 2007 GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F6 · ownership.nature: Held by Flagship Fund 2007 GP. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-026439 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · kind: On October 29, 2019, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"), pro rata and without consideration, 1,469,173 shares of the Issuer's common stock. Flagship Fund IV GP, in turn, distributed to its members, pro rata and without consideration, the 61,537 shares it received from Flagship Fund IV. Noubar B. Afeyan, Ph.D., a manager of Flagship Fund IV GP, received 27,799 shares through Flagship Fund IV GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F1 · price: On October 29, 2019, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"), pro rata and without consideration, 1,469,173 shares of the Issuer's common stock. Flagship Fund IV GP, in turn, distributed to its members, pro rata and without consideration, the 61,537 shares it received from Flagship Fund IV. Noubar B. Afeyan, Ph.D., a manager of Flagship Fund IV GP, received 27,799 shares through Flagship Fund IV GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F1 · balance_after: On October 29, 2019, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"), pro rata and without consideration, 1,469,173 shares of the Issuer's common stock. Flagship Fund IV GP, in turn, distributed to its members, pro rata and without consideration, the 61,537 shares it received from Flagship Fund IV. Noubar B. Afeyan, Ph.D., a manager of Flagship Fund IV GP, received 27,799 shares through Flagship Fund IV GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F5 · ownership.nature: Held by Flagship Fund IV GP. Each of the filing persons other than Flagship Fund IV GP disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-026439 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F3 · kind: On October 29, 2019, Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007") distributed to its limited partners and sole general partner, Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP"), pro rata and without consideration, 1,061,102 shares of the Issuer's common stock. Flagship Fund 2007 GP, in turn, distributed to its members, pro rata and without consideration, the 248,379 shares it received from Flagship Fund 2007. Dr. Afeyan, a manager of Flagship Fund 2007 GP, received 92,796 shares through Flagship Fund 2007 GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F3 · price: On October 29, 2019, Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007") distributed to its limited partners and sole general partner, Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP"), pro rata and without consideration, 1,061,102 shares of the Issuer's common stock. Flagship Fund 2007 GP, in turn, distributed to its members, pro rata and without consideration, the 248,379 shares it received from Flagship Fund 2007. Dr. Afeyan, a manager of Flagship Fund 2007 GP, received 92,796 shares through Flagship Fund 2007 GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F4 · ownership.nature: Shares held by Flagship Fund 2007. Flagship Fund 2007 GP is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-026439 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · kind: On October 29, 2019, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"), pro rata and without consideration, 1,469,173 shares of the Issuer's common stock. Flagship Fund IV GP, in turn, distributed to its members, pro rata and without consideration, the 61,537 shares it received from Flagship Fund IV. Noubar B. Afeyan, Ph.D., a manager of Flagship Fund IV GP, received 27,799 shares through Flagship Fund IV GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F1 · price: On October 29, 2019, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"), pro rata and without consideration, 1,469,173 shares of the Issuer's common stock. Flagship Fund IV GP, in turn, distributed to its members, pro rata and without consideration, the 61,537 shares it received from Flagship Fund IV. Noubar B. Afeyan, Ph.D., a manager of Flagship Fund IV GP, received 27,799 shares through Flagship Fund IV GP's distribution. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F2 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Dr. Afeyan is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein..

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 25

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 486,023 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F8 · derivative.exercise_price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · derivative.exercise_date: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · derivative.expiration_date: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F9 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. serves as sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 24

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 48,602 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F8 · derivative.exercise_price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · derivative.exercise_date: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · derivative.expiration_date: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV-Rx. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 23

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 194,409 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F8 · derivative.exercise_price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · derivative.exercise_date: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F8 · derivative.expiration_date: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 22

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 82,324 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · derivative.exercise_price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · derivative.exercise_date: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · derivative.expiration_date: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV-Rx. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 21

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 335,457 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · derivative.exercise_price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · derivative.exercise_date: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · derivative.expiration_date: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 20

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 120,795 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · derivative.exercise_price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · derivative.exercise_date: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F7 · derivative.expiration_date: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Fund 2007 GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 19

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 545,826 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · derivative.exercise_price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · derivative.exercise_date: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · derivative.expiration_date: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV-Rx. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 18

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 503,840 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · derivative.exercise_price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · derivative.exercise_date: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · derivative.expiration_date: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 17

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 209,933 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · derivative.exercise_price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · derivative.exercise_date: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F5 · derivative.expiration_date: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Fund 2007 GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 16

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 2,255,074 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F3 · derivative.exercise_price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F3 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F3 · derivative.exercise_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F3 · derivative.expiration_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · derivative · entry 15

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 751,691 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F3 · derivative.exercise_price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F3 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F3 · derivative.exercise_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F3 · derivative.expiration_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Fund 2007 GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 14

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 986,023

F9 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. serves as sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 13

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 486,023

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F8 · price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F9 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. serves as sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 12

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 676,752

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F8 · price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV-Rx. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 11

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,288,780

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F8 · price: Each share of Series E Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 10

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 628,150

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV-Rx. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 9

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,094,371

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,761,029

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · price: Each share of Series C Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Fund 2007 GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 545,826

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV-Rx. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 6

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,758,914

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 5

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,640,234

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · price: Each share of Series B Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Fund 2007 GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,255,074

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F3 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-19-029735 · a4.xml · nonDerivative · entry 3

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Opportunities Fund I General Partner LLC · CIK 0001725004 · 10% owner

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,430,301

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F3 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") on a one-for-1.842 basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Fund 2007 GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 13

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 132,817 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F3 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 12

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 128,845 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 11

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 171,428 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 10

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 359,276 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 9

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund IV, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 283,460 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund IV, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 400,000 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund IV, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 571,428 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 6

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 1,061,102

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 5

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund IV, L.P.

Disclosed balance after: 1,469,173

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 268,736

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund 2007, L.P.

Disclosed balance after: 0

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund IV, L.P.

Disclosed balance after: 214,285

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund IV, L.P.

Disclosed balance after: 0

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · derivative · entry 9

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 281,203 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F6 · derivative.exercise_price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.exercise_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.expiration_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · derivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 173,586 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F6 · derivative.exercise_price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.exercise_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.expiration_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship 2007 GP") is the general partner of Flagship 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. While Mr. Kania is retired from Flagship Pioneering, Inc., he continue to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · derivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 665,908 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F4 · derivative.exercise_price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F4 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F4 · derivative.exercise_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F4 · derivative.expiration_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · nonDerivative · entry 6

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 947,111

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · nonDerivative · entry 5

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 216,451

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship 2007 GP") is the general partner of Flagship 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. While Mr. Kania is retired from Flagship Pioneering, Inc., he continue to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 665,908

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F4 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 8

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 106,787

F7 · price: The transactions were executed in multiple trades at prices ranging from $3.10 to $3.15. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV-Rx. Each of the filing persons, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 7

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 426,885

F7 · price: The transactions were executed in multiple trades at prices ranging from $3.10 to $3.15. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 6

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 117,080

F6 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.16. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV-Rx. Each of the filing persons, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 5

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 468,063

F6 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.16. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.