STANTON THOMAS R

SEC source: 0001193125-26-142009 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,126,553.51

F1 · kind: Represents a grant of restricted stock units that vest in four equal and annual installments beginning on the first anniversary date of the grant.

SEC source: 0001193125-26-024818 · ownership.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 939,904.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001193125-26-027411 · ownership.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 955,470.51

F2 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted performance stock units.

SEC source: 0001193125-26-027411 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 967,877.51

F1 · kind: These shares represent the vesting of performance stock units that were awarded pursuant to a grant on January 20, 2023 under the Amended and Restated ADTRAN Holdings, Inc. 2020 Employee Stock Incentive Plan.

SEC source: 0001193125-26-024818 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 954,313.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001193125-26-019455 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 971,848.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001193125-25-295709 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 982,095.51

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $7.32 to $7.33, inclusive. The reporting person undertakes to provide to ADTRAN Holdings, Inc. (the Issuer), any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote (1) to this Form 4.

SEC source: 0001193125-25-288073 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 941,167.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-25-095931 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 944,522.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-25-054336 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 950,185.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-25-009862 · ownership.xml · nonDerivative · entry 4

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 955,593.51

F4 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-25-009862 · ownership.xml · nonDerivative · entry 3

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 965,129.51

F3 · kind: Represents a grant of restricted stock units that vest in four equal and annual installments beginning on the first anniversary date of the grant. Remarks:

SEC source: 0000950170-25-009862 · ownership.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 805,285.51

F2 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted performance stock units.

SEC source: 0000950170-25-009862 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 815,592.51

F1 · kind: These shares represent the vesting of performance stock units that were awarded pursuant to a grant on March 1, 2023 under the Amended and Restated ADTRAN Holdings, Inc. 2020 Employee Stock Incentive Plan.

SEC source: 0001193125-26-093935 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 815,952.51

F1 · shares: On January 28, 2025, the Reporting Person filed a Form 4 which inadvertently understated, by 360 shares, the number of shares received upon the settlement of performance stock units that were granted on March 1, 2023 under the Amended and Restated ADTRAN Holdings, Inc. 2020 Employee Stock Incentive Plan. This amendment is being filed to correct the number of shares received and the total number of shares directly held by the Reporting Person following such settlement.

F1 · balance_after: On January 28, 2025, the Reporting Person filed a Form 4 which inadvertently understated, by 360 shares, the number of shares received upon the settlement of performance stock units that were granted on March 1, 2023 under the Amended and Restated ADTRAN Holdings, Inc. 2020 Employee Stock Incentive Plan. This amendment is being filed to correct the number of shares received and the total number of shares directly held by the Reporting Person following such settlement.

F2 · balance_after: As a result of this amendment, the reporting person beneficially owns a total of 955,830.51 shares as of the date hereof and not 955,470.51 shares as reported on the most recent Form 4 filed by the reporting person on January 28, 2028.

SEC source: 0000950170-25-007831 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 776,217.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-25-005822 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 782,612.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-24-128540 · ownership.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 788,630.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-24-128540 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 805,403.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-24-114665 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 810,975.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-24-083957 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 784,080.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-24-084280 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 814,723.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

F2 · shares: On July 16, 2024, the Reporting Person filed a Form 4 which inadvertently overstated the number of shares withheld for taxes in connection with the vesting event reported therein. This amendment is being filed to correct the number of shares withheld and the total number of shares directly held by the Reporting Person following such withholding.

F2 · balance_after: On July 16, 2024, the Reporting Person filed a Form 4 which inadvertently overstated the number of shares withheld for taxes in connection with the vesting event reported therein. This amendment is being filed to correct the number of shares withheld and the total number of shares directly held by the Reporting Person following such withholding.

SEC source: 0000950170-24-008901 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 856,629.51

F1 · kind: Represents a grant of restricted stock units that vest in four equal and annual installments beginning on the first anniversary date of the grant.

SEC source: 0000950170-24-006531 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 726,671.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-23-065084 · ownership.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 737,488.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-23-065084 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 740,843.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000950170-23-064810 · ownership.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 768,699.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001209191-23-048667 · doc4.xml · derivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 225,774.587

Underlying: Common Stock · 2,340.361 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.exercise_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.expiration_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

SEC source: 0001209191-23-035516 · doc4.xml · derivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 223,434.226

Underlying: Common Stock · 2,262.345 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.exercise_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.expiration_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

SEC source: 0001209191-23-020788 · doc4.xml · derivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 221,171.881

Underlying: Common Stock · 1,241.097 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.exercise_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.expiration_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

SEC source: 0001209191-23-004634 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 776,097.51

F1 · kind: Represents a grant of restricted stock units that vest in four equal and annual installments beginning on the first anniversary date of the grant.

SEC source: 0001209191-23-001148 · doc4.xml · derivative · entry 3

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 219,930.784

Underlying: Common Stock · 60,320 shares

Expires not disclosed

F3 · derivative.exercise_price: Represents shares of phantom stock of the Issuer held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F2 · kind: Upon vesting 60,320 restricted stock units previously granted to the reporting person were deferred resulting in the reporting person's receipt of phantom stock pursuant to the Issuer's equity deferral program.

F3 · derivative.exercise_date: Represents shares of phantom stock of the Issuer held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F3 · derivative.expiration_date: Represents shares of phantom stock of the Issuer held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

SEC source: 0001209191-23-001148 · doc4.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 688,951.51

F2 · kind: Upon vesting 60,320 restricted stock units previously granted to the reporting person were deferred resulting in the reporting person's receipt of phantom stock pursuant to the Issuer's equity deferral program.

SEC source: 0001209191-23-001148 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 749,271.51

F1 · kind: Shares delivered to the Issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001209191-22-060553 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 805,764.51

F1 · security: Reflects shares acquired through the automatic reinvestment of dividends paid on the Company's common stock.

SEC source: 0001209191-22-060393 · doc4.xml · derivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 159,610.784

Underlying: Common Stock · 693.943 shares

Expires not disclosed

F1 · derivative.exercise_price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.exercise_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

F1 · derivative.expiration_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares.

SEC source: 0001209191-22-058138 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 805,112.282

F1 · kind: Shares delivered to the issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001209191-22-057822 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 808,467.282

F1 · kind: Shares delivered to the issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001209191-22-057614 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 814,038.282

F1 · kind: Shares delivered to the issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0001209191-22-056659 · doc4.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 851,023.282

F1 · kind: Shares delivered to the issuer for the payment of withholding taxes due upon the vesting of previously granted restricted stock units.

SEC source: 0000926282-22-000056 · primary_doc.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 855,753.282

F1 · security: Reflects shares acquired through the automatic reinvestment of dividends paid on the issuer's common stock.

SEC source: 0000926282-22-000056 · primary_doc.xml · derivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 158,916.841

Underlying: Common Stock · 619.169 shares

Expires not disclosed

F2 · derivative.exercise_price: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the issuer's deferred compensation plan. The phantom shares become payable in cash six months after the reporting person's separation of service with the issuer.

F2 · derivative.exercise_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the issuer's deferred compensation plan. The phantom shares become payable in cash six months after the reporting person's separation of service with the issuer.

F2 · derivative.expiration_date: Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock held in the reporting person's account under the issuer's deferred compensation plan. The phantom shares become payable in cash six months after the reporting person's separation of service with the issuer.

SEC source: 0000926282-22-000048 · primary_doc.xml · derivative · entry 6

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 69,473 shares

Expires 2022-11-06

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_date: The options granted to the reporting person vested in four annual installments beginning on the anniversary of the date of grant and were fully vested prior to the Effective Time.

SEC source: 0000926282-22-000048 · primary_doc.xml · derivative · entry 5

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 5,893 shares

Expires 2022-11-06

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_date: The options granted to the reporting person vested in four annual installments beginning on the anniversary of the date of grant and were fully vested prior to the Effective Time.

SEC source: 0000926282-22-000048 · primary_doc.xml · nonDerivative · entry 4

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 855,457.09

F2 · kind: Represents shares surrendered to Adtran Holdings, Inc. to cover the exercise price of outstanding stock options. The reporting person received 11,606 shares of common stock on the net exercise of stock options to purchase 69,473 shares of common stock. The reporting person surrendered 57,867 shares of common stock underlying the stock options for payment of the exercise price and tax withholding, using the closing stock price on August 10, 2022 of $24.25, pursuant to the terms of the 2006 Employee Stock Incentive Plan.

SEC source: 0000926282-22-000048 · primary_doc.xml · nonDerivative · entry 3

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 913,324.09

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.

SEC source: 0000926282-22-000048 · primary_doc.xml · nonDerivative · entry 2

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 843,851.09

F1 · kind: Represents shares surrendered to Adtran Holdings, Inc. to cover the exercise price of outstanding stock options. The reporting person received 1,769 shares of common stock on the net exercise of stock options to purchase 5,893 shares of common stock. The reporting person surrendered 4,124 shares of common stock underlying the stock options for payment of the exercise price, using the closing stock price on August 10, 2022 of $24.25, pursuant to the terms of the 2006 Employee Stock Incentive Plan.

SEC source: 0000926282-22-000048 · primary_doc.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 847,975.09

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.

SEC source: 0000926282-22-000044 · primary_doc.xml · nonDerivative · entry 1

STANTON THOMAS R · CIK 0001191219 · Director · Chairman, CEO and President

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 842,082.09

F1 · security: Represents a grant of restricted stock units ("RSUs") with 75% vesting in 24 months, 6.25% vesting in 27 months, 6.25% vesting in 30 months, 6.25% vesting in 33 months and 6.25% vesting in 36 months following the date of grant.

F2 · balance_after: Includes 648,483 time-based RSUs that settle upon vesting in shares of the Issuer's common stock.

SEC source: 0001209191-22-041659 · doc4.xml · derivative · entry 10

STANTON THOMAS R · CIK 0001191219 · Director · Chairman and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 158,297.672 shares

Expires not disclosed

F2 · derivative.exercise_price: Pursuant to that certain Business Combination Agreement, dated August 30, 2021, by and among the Issuer, ADVA Optical Networking SE, Acorn HoldCo, Inc. (now named ADTRAN Holdings, Inc. ("Holdings")), and Acorn MergeCo, Inc., the Issuer became a wholly owned subsidiary of Holdings on July 8, 2022 (the "Effective Time"). At the Effective Time, (a) each share of the Issuer's common stock converted, on a one-for-one basis, into a share of Holdings' common stock; (b) each RSU measured in shares of the Issuer's common stock, whether vested or unvested, converted, on a one-for-one basis, into an RSU measured in shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding RSU immediately prior to the Effective Time;

F3 · derivative.exercise_price: (Continued from footnote 2) (c) each option to purchase the Issuer's common stock converted, on a one-for-one basis, into an option to purchase shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding option immediately prior to the Effective Time; and (d) each share of phantom stock of the Issuer (representing the economic equivalent of one share of the Issuer's common stock) converted, on a one-for-one basis, into a share of phantom stock of Holdings on the same terms and conditions as were applicable to the corresponding phantom stock immediately prior to the Effective Time.

F2 · price: Pursuant to that certain Business Combination Agreement, dated August 30, 2021, by and among the Issuer, ADVA Optical Networking SE, Acorn HoldCo, Inc. (now named ADTRAN Holdings, Inc. ("Holdings")), and Acorn MergeCo, Inc., the Issuer became a wholly owned subsidiary of Holdings on July 8, 2022 (the "Effective Time"). At the Effective Time, (a) each share of the Issuer's common stock converted, on a one-for-one basis, into a share of Holdings' common stock; (b) each RSU measured in shares of the Issuer's common stock, whether vested or unvested, converted, on a one-for-one basis, into an RSU measured in shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding RSU immediately prior to the Effective Time;

F3 · price: (Continued from footnote 2) (c) each option to purchase the Issuer's common stock converted, on a one-for-one basis, into an option to purchase shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding option immediately prior to the Effective Time; and (d) each share of phantom stock of the Issuer (representing the economic equivalent of one share of the Issuer's common stock) converted, on a one-for-one basis, into a share of phantom stock of Holdings on the same terms and conditions as were applicable to the corresponding phantom stock immediately prior to the Effective Time.

F2 · derivative.exercise_date: Pursuant to that certain Business Combination Agreement, dated August 30, 2021, by and among the Issuer, ADVA Optical Networking SE, Acorn HoldCo, Inc. (now named ADTRAN Holdings, Inc. ("Holdings")), and Acorn MergeCo, Inc., the Issuer became a wholly owned subsidiary of Holdings on July 8, 2022 (the "Effective Time"). At the Effective Time, (a) each share of the Issuer's common stock converted, on a one-for-one basis, into a share of Holdings' common stock; (b) each RSU measured in shares of the Issuer's common stock, whether vested or unvested, converted, on a one-for-one basis, into an RSU measured in shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding RSU immediately prior to the Effective Time;

F3 · derivative.exercise_date: (Continued from footnote 2) (c) each option to purchase the Issuer's common stock converted, on a one-for-one basis, into an option to purchase shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding option immediately prior to the Effective Time; and (d) each share of phantom stock of the Issuer (representing the economic equivalent of one share of the Issuer's common stock) converted, on a one-for-one basis, into a share of phantom stock of Holdings on the same terms and conditions as were applicable to the corresponding phantom stock immediately prior to the Effective Time.

F2 · derivative.expiration_date: Pursuant to that certain Business Combination Agreement, dated August 30, 2021, by and among the Issuer, ADVA Optical Networking SE, Acorn HoldCo, Inc. (now named ADTRAN Holdings, Inc. ("Holdings")), and Acorn MergeCo, Inc., the Issuer became a wholly owned subsidiary of Holdings on July 8, 2022 (the "Effective Time"). At the Effective Time, (a) each share of the Issuer's common stock converted, on a one-for-one basis, into a share of Holdings' common stock; (b) each RSU measured in shares of the Issuer's common stock, whether vested or unvested, converted, on a one-for-one basis, into an RSU measured in shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding RSU immediately prior to the Effective Time;

F3 · derivative.expiration_date: (Continued from footnote 2) (c) each option to purchase the Issuer's common stock converted, on a one-for-one basis, into an option to purchase shares of Holdings' common stock on the same terms and conditions as were applicable to the corresponding option immediately prior to the Effective Time; and (d) each share of phantom stock of the Issuer (representing the economic equivalent of one share of the Issuer's common stock) converted, on a one-for-one basis, into a share of phantom stock of Holdings on the same terms and conditions as were applicable to the corresponding phantom stock immediately prior to the Effective Time.