Flagship Pioneering Special Opportunities Fund II, L.P.

SEC source: 0001104659-20-134302 · tm2037869-3_4seq1.xml · derivative · entry 4

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 4,074,074 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.

F1 · derivative.exercise_price: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · kind: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · price: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · derivative.exercise_date: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · derivative.expiration_date: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-20-134302 · tm2037869-3_4seq1.xml · derivative · entry 3

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 4,444,444 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.

F1 · derivative.exercise_price: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · kind: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · price: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · derivative.exercise_date: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · derivative.expiration_date: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-20-134302 · tm2037869-3_4seq1.xml · nonDerivative · entry 2

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 1,481,481

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.

F1 · kind: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · price: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F3 · ownership.nature: Shares held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Opportunities Fund II GP. Noubar B. Afeyan, Ph.D. is sole director of Flagship Pioneering. Each of Noubar B. Afeyan Ph.D., Flagship Pioneering, and Opportunities Fund II GP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-20-134302 · tm2037869-3_4seq1.xml · nonDerivative · entry 1

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 8,888,888

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.

F1 · kind: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F1 · price: Upon closing of the Registrant's initial public offering, each share of Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock and Series B Convertible Preferred Stock automatically converted into shares of Common Stock without payment or further consideration. There was no expiration date for the Series A Convertible Preferred Stock, Series A-1 Convertible Preferred Stock or Series B Convertible Preferred Stock.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · derivative · entry 13

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 1,801,801 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.

F1 · derivative.exercise_price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.exercise_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.expiration_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F4 · ownership.nature: Shares held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Opportunities Fund II GP. Noubar B. Afeyan, Ph.D. is sole director of Flagship Pioneering. Each of Noubar B. Afeyan Ph.D., Flagship Pioneering, and Opportunities Fund II GP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · derivative · entry 12

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 1,441,441 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.

F1 · derivative.exercise_price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.exercise_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.expiration_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F3 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Opportunities Fund I GP") is the general partner of Flagship Opportunities Fund I. Noubar B. Afeyan Ph.D. serves as the sole manager of Opportunities Fund I GP. Each of Opportunities Fund I GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · derivative · entry 11

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 722,320 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.

F1 · derivative.exercise_price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.exercise_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.expiration_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · derivative · entry 10

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 4,504,504 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.

F1 · derivative.exercise_price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.exercise_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.expiration_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · derivative · entry 9

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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

Underlying: Common Stock · 4,054,054 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.

F1 · derivative.exercise_price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.exercise_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F1 · derivative.expiration_date: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 8

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 1,851,801

F4 · ownership.nature: Shares held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Opportunities Fund II GP. Noubar B. Afeyan, Ph.D. is sole director of Flagship Pioneering. Each of Noubar B. Afeyan Ph.D., Flagship Pioneering, and Opportunities Fund II GP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 7

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 1,801,801

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.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F4 · ownership.nature: Shares held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Opportunities Fund II GP. Noubar B. Afeyan, Ph.D. is sole director of Flagship Pioneering. Each of Noubar B. Afeyan Ph.D., Flagship Pioneering, and Opportunities Fund II GP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 6

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 1,491,441

F3 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Opportunities Fund I GP") is the general partner of Flagship Opportunities Fund I. Noubar B. Afeyan Ph.D. serves as the sole manager of Opportunities Fund I GP. Each of Opportunities Fund I GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 5

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 1,441,441

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.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F3 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Opportunities Fund I GP") is the general partner of Flagship Opportunities Fund I. Noubar B. Afeyan Ph.D. serves as the sole manager of Opportunities Fund I GP. Each of Opportunities Fund I GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 9,330,878

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 9,280,878

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.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 8,558,558

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.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-029693 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II General Partner LLC · CIK 0001826217 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

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

Flagship Pioneering Special Opportunities Fund II, L.P. · CIK 0001761283 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 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: 4,054,054

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.

F1 · price: The Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") is convertible into the number of shares of the Registrant's common stock shown in Table II, column 7 and has no expiration date. The Preferred Stock automatically converted into common stock upon the closing of the Registrant's initial public offering, which occurred on October 27, 2020.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan Ph.D. serves as the sole manager of Fund V GP. Each of Fund V GP and Noubar B. Afeyan Ph.D. disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.