Frost Mark T

SEC source: 0001171843-26-002156 · ownership.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 47,500

F1 · balance_after: Includes (a) an award granting 30,000 restricted stock units (RSUs) that will vest in three equal installments on March 20, 2027, 2028, and 2029, subject to the terms set forth in an award agreement between the Issuer and the Reporting Person, (b) 5,000 shares of common stock purchased on March 16, 2026, (c) 10,000 RSUs that will vest on May 12, 2026, and (d) 2,500 shares of common stock beneficially owned by the Reporting Person.

F2 · balance_after: On March 13, 2026, the common stock of Harvard Bioscience, Inc. underwent a reverse stock split in a ratio of 10-for-1. The 10,000 RSUs referenced in Footnote 1(c) were previously reported as covering 100,000 RSUs and the 2,500 shares of common stock referenced in Footnote 1(d) were previously reported as covering 25,000 shares of common stock. These numbers have been adjusted to reflect the stock split that occurred on March 13, 2026.

SEC source: 0001171843-26-002155 · ownership.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,500

F1 · balance_after: Includes (a) 5,000 shares of common stock purchased on March 16, 2026, (b) 10,000 restricted stock units that will vest on May 12, 2026, and (c) 2,500 shares of common stock beneficially owned by the Reporting Person.

F2 · balance_after: On March 13, 2026, the common stock of Harvard Bioscience, Inc. underwent a reverse stock split in a ratio of 10-for-1. The 10,000 restricted stock units referenced in Footnote 1(b) were previously reported as covering 100,000 restricted stock units and the 2,500 shares of common stock referenced in Footnote 1(c) were previously reported as covering 25,000 shares of common stock. These numbers have been adjusted to reflect the stock split that occurred on March 13, 2026.

SEC source: 0001104659-25-048461 · tm2514961-2_4seq1.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Interim CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 125,000

F1 · shares: Represents 100,000 restricted stock units that will vest on May 12, 2026.

F2 · balance_after: Includes (a) 100,000 restricted stock units that will vest on May 12, 2026, and (b) 25,000 shares of common stock beneficially owned by the Reporting Person.

SEC source: 0000950170-24-046565 · ownership.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Director · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 35,351

F1 · date: This Form 4 is being filed late due to inadvertent administrative error.

F2 · kind: Shares forfeited to satisfy the mandatory tax withholding requirement upon vesting of restricted shares. This is not an open market sale of securities.

F3 · balance_after: On September 28, 2023, the Class A Common Stock of the Issuer underwent a 1-for-20 reverse stock split (the "Reverse Stock Split"). The amounts of securities listed herein have been adjusted to reflect the effect of the Reverse Stock Split.

SEC source: 0000950170-24-021437 · ownership.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Director · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 36,720

F1 · kind: Shares forfeited to satisfy the mandatory tax withholding requirement upon vesting of restricted shares. This is not an open market sale of securities.

F2 · balance_after: On September 28, 2023, the Class A Common Stock of the Issuer underwent a 1-for-20 reverse stock split (the "Reverse Stock Split"). The amounts of securities listed herein have been adjusted to reflect the effect of the Reverse Stock Split.

SEC source: 0000899243-23-012784 · doc4.xml · derivative · entry 2

Frost Mark T · CIK 0001310262 · Director · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 440,675

Underlying: Class A Common Stock · 440,675 shares

Expires 2030-04-03

F1 · security: This transaction is being reported late due to inadvertent administrative error.

F3 · security: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, April 3, 2026. The options expire on April 3, 2030.

F3 · shares: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, April 3, 2026. The options expire on April 3, 2030.

F3 · price: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, April 3, 2026. The options expire on April 3, 2030.

F3 · derivative.exercise_date: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, April 3, 2026. The options expire on April 3, 2030.

SEC source: 0000899243-23-012784 · doc4.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Director · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 738,352

F1 · security: This transaction is being reported late due to inadvertent administrative error.

F2 · security: Represents shares of Class A Common Stock underlying Restricted Stock Units ("RSUs") issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each RSU represents the contingent right to receive one share of the Issuer's Class A Common Stock. These RSUs vest ratably over three years.

F2 · price: Represents shares of Class A Common Stock underlying Restricted Stock Units ("RSUs") issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each RSU represents the contingent right to receive one share of the Issuer's Class A Common Stock. These RSUs vest ratably over three years.

SEC source: 0000899243-23-008059 · doc4.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 503,325

F1 · kind: The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting and settlement of restricted stock units. The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary transaction by the Reporting Person.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.165 to $1.236. The Reporting Person undertakes to provide the Issuer, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

SEC source: 0000899243-22-015019 · doc4.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 528,265

F1 · kind: Shares forfeited to satisfy the mandatory tax withholding requirement upon vesting of restricted shares. This is not an open market sale of securities.

F2 · balance_after: Includes an updated total share amount that includes 134,632 shares of Class A Common Stock that was inadvertently omitted from the total of Class A Common Stock beneficially owned in the Reporting Person's March 1, 2022 Form 4.

SEC source: 0000899243-22-020544 · doc4a.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 529,192

F1 · kind: Shares forfeited to satisfy the mandatory tax withholding requirement upon vesting of restricted shares. This is not an open market sale of securities.

F2 · balance_after: Includes an updated total share amount that includes 134,632 shares of Class A Common Stock that were reflected in the original Form 4 filed by the Reporting Person on April 18, 2022 but were inadvertently omitted from the total of Class A Common Stock beneficially owned in the Reporting Person's March 1, 2022 Form 4.

SEC source: 0000899243-22-037811 · doc4a.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 508,997

F1 · kind: Shares forfeited to satisfy the mandatory tax withholding requirement upon vesting of restricted shares. This is not an open market sale of securities.

SEC source: 0000899243-22-008436 · doc4.xml · derivative · entry 2

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 69,125

Underlying: Class A Common Stock · 69,125 shares

Expires 2029-02-25

F2 · security: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, February 25, 2025. The options expire on February 25, 2029.

F2 · price: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, February 25, 2025. The options expire on February 25, 2029.

F2 · derivative.exercise_date: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, February 25, 2025. The options expire on February 25, 2029.

SEC source: 0000899243-22-008436 · doc4.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 437,642

F1 · security: Represents shares of Class A Common Stock underlying Restricted Stock Units ("RSUs") issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each RSU represents the contingent right to receive one share of the Issuer's Class A Common Stock. These RSUs vest ratably over three years.

F1 · price: Represents shares of Class A Common Stock underlying Restricted Stock Units ("RSUs") issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each RSU represents the contingent right to receive one share of the Issuer's Class A Common Stock. These RSUs vest ratably over three years.

SEC source: 0000899243-22-015207 · doc4a.xml · derivative · entry 2

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 69,125

Underlying: Class A Common Stock · 69,125 shares

Expires 2029-02-25

F2 · security: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, February 25, 2025. The options expire on February 25, 2029.

F2 · price: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, February 25, 2025. The options expire on February 25, 2029.

F2 · derivative.exercise_date: Represents stock options issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each stock option represents the right to purchase one share of the Issuer's Class A Common Stock. The stock options vest ratably over three years and become exercisable as to 100% of the shares of Class A Common Stock on the third anniversary of the grant date, February 25, 2025. The options expire on February 25, 2029.

SEC source: 0000899243-22-015207 · doc4a.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 572,274

F1 · security: Represents shares of Class A Common Stock underlying Restricted Stock Units ("RSUs") issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each RSU represents the contingent right to receive one share of the Issuer's Class A Common Stock. These RSUs vest ratably over three years.

F1 · price: Represents shares of Class A Common Stock underlying Restricted Stock Units ("RSUs") issued under the Fathom Digital Manufacturing Corporation 2021 Omnibus Incentive Plan, as amended and/or restated from time to time. Each RSU represents the contingent right to receive one share of the Issuer's Class A Common Stock. These RSUs vest ratably over three years.

SEC source: 0000899243-16-035040 · doc4.xml · derivative · entry 3

Frost Mark T · CIK 0001310262 · SVP, CFO & Treasurer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,137

Underlying: Common Stock · 2,137 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 time-based Restricted Stock Units (RSUs) will vest in two equal installments beginning 1 year after grant date of 12/3/2015.

F1 · derivative.exercise_date: The time-based Restricted Stock Units (RSUs) will vest in two equal installments beginning 1 year after grant date of 12/3/2015.

F1 · derivative.expiration_date: The time-based Restricted Stock Units (RSUs) will vest in two equal installments beginning 1 year after grant date of 12/3/2015.

SEC source: 0000899243-16-035040 · doc4.xml · nonDerivative · entry 2

Frost Mark T · CIK 0001310262 · SVP, CFO & Treasurer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,571

SEC source: 0000899243-16-035040 · doc4.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · SVP, CFO & Treasurer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,137

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 time-based Restricted Stock Units (RSUs) will vest in two equal installments beginning 1 year after grant date of 12/3/2015.

SEC source: 0000899243-16-035508 · doc4a.xml · nonDerivative · entry 1

Frost Mark T · CIK 0001310262 · SVP, CFO & Treasurer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,442

F1 · shares: This is being amended to correct the amount of shares forfeited and the amount of securities beneficially owned following the reported transaction.

F1 · balance_after: This is being amended to correct the amount of shares forfeited and the amount of securities beneficially owned following the reported transaction.

SEC source: 0000899243-16-029238 · doc4.xml · derivative · entry 2

Frost Mark T · CIK 0001310262 · SVP, CFO & Treasurer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,169

Underlying: Common Stock · 2,169 shares

Expires not disclosed

F2 · derivative.exercise_price: The time-based Restricted Stock Units (RSUs) will cliff vest on July 31, 2019. On that date, the RSUs will be converted to common stock and a like number of shares will be issued to the grantee.

F2 · derivative.exercise_date: The time-based Restricted Stock Units (RSUs) will cliff vest on July 31, 2019. On that date, the RSUs will be converted to common stock and a like number of shares will be issued to the grantee.

F2 · derivative.expiration_date: The time-based Restricted Stock Units (RSUs) will cliff vest on July 31, 2019. On that date, the RSUs will be converted to common stock and a like number of shares will be issued to the grantee.

SEC source: 0000899243-16-029238 · doc4.xml · derivative · entry 1

Frost Mark T · CIK 0001310262 · SVP, CFO & Treasurer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 4,363

Underlying: Common Stock · 4,363 shares

Expires not disclosed

F1 · derivative.exercise_price: The number of Restricted Stock Units ("RSUs)" represents the target number of RSUs that may be earned based on the achievement of certain performance criteria. The actual number of RSUs awarded will vary depending on the Company's performance. The performance period will end on July 31, 2019. Thereafter, a determination will be made as to whether and to what extent the performance criteria has been met. If such criteria has been met, the RSUs earned will be converted to common stock and a like number of shares will be issued to the grantee.

F1 · derivative.exercise_date: The number of Restricted Stock Units ("RSUs)" represents the target number of RSUs that may be earned based on the achievement of certain performance criteria. The actual number of RSUs awarded will vary depending on the Company's performance. The performance period will end on July 31, 2019. Thereafter, a determination will be made as to whether and to what extent the performance criteria has been met. If such criteria has been met, the RSUs earned will be converted to common stock and a like number of shares will be issued to the grantee.

F1 · derivative.expiration_date: The number of Restricted Stock Units ("RSUs)" represents the target number of RSUs that may be earned based on the achievement of certain performance criteria. The actual number of RSUs awarded will vary depending on the Company's performance. The performance period will end on July 31, 2019. Thereafter, a determination will be made as to whether and to what extent the performance criteria has been met. If such criteria has been met, the RSUs earned will be converted to common stock and a like number of shares will be issued to the grantee.