Samuels Theodore R. II

SEC source: 0001020569-26-000077 · wk-form4_1791490219.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,215.49

Underlying: Common Stock · 310.49 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-26-000073 · wk-form4_1791237334.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,905

Underlying: Common Stock · 104.67 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-26-000182 · wk-form4_1790800538.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,795.979

F1 · balance_after: Ownership includes 3,992 shares of previously-granted restricted stock units subject to vesting requirements.

SEC source: 0001688276-26-000010 · wk-form4_1790972748.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 71,859.041

Underlying: Common Stock, $0.10 par value · 821.314 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-26-000063 · wk-form4_1783456307.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,800.33

Underlying: Common Stock · 99.06 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-26-000061 · wk-form4_1783370069.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,701.27

Underlying: Common Stock · 310.86 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-26-000142 · wk-form4_1782942435.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,212.979

F1 · balance_after: Ownership includes 3,992 shares of restricted stock units subject to vesting requirements.

SEC source: 0001688276-26-000008 · wk-form4_1783023508.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 70,360.664

Underlying: Common Stock, $0.10 par value · 889.448 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001071739-26-000114 · wk-form4_1778707077.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 24,747.979

F1 · shares: This award includes 3,992 shares of restricted stock units which will vest in full on the earlier of May 12, 2027, or the date of the Registrant's next annual meeting of stockholders.

SEC source: 0001020569-26-000051 · wk-form4_1778535024.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,390.41

Underlying: Common Stock · 1,892 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan ("DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: Consists of shares issuable upon the settlement of restricted stock units ("RSUs") granted on May 7, 2026. The RSUs vest in their entirety on the grant date. The Reporting Person has elected that upon vesting of RSUs, receipt of the shares of Common Stock be deferred under the DDCP; accordingly, upon vesting, the Reporting Person will instead receive an equal number of Phantom Shares.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan ("DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan ("DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-26-000030 · wk-form4_1775592861.xml · derivative · entry 2

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,498.41

Underlying: Common Stock · 92.27 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F4 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F5 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $103.45 to $103.54, inclusive. The Reporting Person undertakes to provide the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (5).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-26-000030 · wk-form4_1775592861.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,406.14

Underlying: Common Stock · 349.88 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $103.54 to $103.62, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-26-000088 · wk-form4_1774994528.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 20,755.979

F1 · balance_after: Ownership includes 3,579 shares of restricted stock units subject to vesting requirements.

SEC source: 0001688276-26-000006 · wk-form4_1775161640.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 68,727.516

Underlying: Common Stock, $0.10 par value · 845.012 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001688276-26-000004 · wk-form4_1770154440.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 67,882.504

Underlying: Common Stock, $0.10 par value · 3,996.367 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-26-000002 · wk-form4_1767911345.xml · derivative · entry 2

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,056.26

Underlying: Common Stock · 107.445 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F4 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F5 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $84.304 to $84.979, inclusive. The Reporting Person undertakes to provide the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (5).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-26-000002 · wk-form4_1767911345.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,948.815

Underlying: Common Stock · 425.125 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $85.254 to $85.279, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-26-000007 · wk-form4_1767650141.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,812.979

F1 · balance_after: Ownership includes 3,579 shares of restricted stock units subject to vesting requirements.

SEC source: 0001688276-26-000002 · wk-form4_1767647710.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 63,174.032

Underlying: Common Stock, $0.10 par value · 926.956 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-25-000189 · wk-form4_1759867860.xml · derivative · entry 2

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,523.69

Underlying: Common Stock · 331.138 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F4 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F5 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $105.569 to $105.819, inclusive. The Reporting Person undertakes to provide the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (5).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-25-000189 · wk-form4_1759867860.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,192.552

Underlying: Common Stock · 76.052 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $104.349 to $104.524, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock acquired at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-25-000177 · wk-form4_1759355222.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,204.979

F1 · balance_after: Ownership includes 3,579 shares of restricted stock units subject to vesting requirements.

SEC source: 0001688276-25-000006 · wk-form4_1759443526.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 61,419.604

Underlying: Common Stock, $0.10 par value · 1,108.647 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001071739-25-000153 · wk-form4_1753826508.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · By family trust

Disclosed balance after: 32,000

F1 · ownership.nature: Owned by a revocable family trust, of which Mr. Samuels serves as a co-trustee.

SEC source: 0001020569-25-000160 · wk-form4_1752009078.xml · derivative · entry 2

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,116.5

Underlying: Common Stock · 347.908 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F4 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the board of directors of the Company as if reinvested in Phantom Shares.

F5 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were sold in multiple transactions at prices ranging from $100.539 to $100.624, inclusive. The Reporting Person undertakes to provide the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (5).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-25-000160 · wk-form4_1752009078.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,768.592

Underlying: Common Stock · 75.666 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were sold in multiple transactions at prices ranging from $100.419 to $100.594, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-25-000140 · wk-form4_1751489884.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,494.979

F1 · balance_after: Ownership includes 3,579 shares of restricted stock units subject to vesting requirements.

SEC source: 0000014272-25-000119 · wk-form4_1751406284.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 59,477.227

Underlying: Common Stock, $0.10 par value · 1,080.147 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-25-000134 · wk-form4_1748896074.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,692.926

Underlying: Common Stock · 2,249 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan (the "DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: Consists of shares issuable upon the settlement of restricted stock units ("RSUs") granted on May 29, 2025. The RSUs vest in their entirety on the grant date. The Reporting Person has elected that upon vesting of RSUs, receipt of the shares of Common Stock be deferred under the DDCP; accordingly, upon vesting, the Reporting Person will instead receive an equal number of Phantom Shares.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan (the "DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan (the "DDCP"), the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-25-000106 · wk-form4_1747257746.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,031.979

F1 · shares: This award includes 3,579 shares of restricted stock units which will vest in full on the earlier of May 13, 2026, or the date of the Registrant's next annual meeting of stockholders.

SEC source: 0001020569-25-000076 · wk-form4_1744063245.xml · derivative · entry 2

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 7,443.926

Underlying: Common Stock · 68.262 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F3 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F4 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $79.524 to $80.259, inclusive. The Reporting Person undertakes to provide the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-25-000076 · wk-form4_1744063245.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 7,375.664

Underlying: Common Stock · 420.226 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · price: The price reported in Column 8 is a weighted average price. These shares of Common Stock were acquired in multiple transactions at prices ranging from $83.209 to $83.344, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-25-000071 · wk-form4_1743628002.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,452.979

F1 · balance_after: Ownership includes 2,916 shares of restricted stock units subject to vesting requirements.

SEC source: 0000014272-25-000083 · wk-form4_1743544941.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 57,676.273

Underlying: Common Stock, $0.10 par value · 819.807 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0000014272-25-000030 · wk-form4_1738715246.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,856.466

Underlying: Common Stock, $0.10 par value · 3,562.341 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-25-000019 · wk-form4_1736371448.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,691.438

Underlying: Common Stock · 45.732 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated common stock ("Common Stock") were sold in multiple transactions at prices ranging from $103.329 to $103.734, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-25-000015 · wk-form4_1736290304.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,645.706

Underlying: Common Stock · 283.482 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the Iron Mountain Incorporated board of directors as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated common stock ("Common Stock") were sold in multiple transactions at prices ranging from $105.744 to $105.969, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-25-000010 · wk-form4_1735941196.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,036.979

F1 · balance_after: Ownership includes 2,916 shares of restricted stock units subject to vesting requirements.

SEC source: 0000014272-25-000008 · wk-form4_1735860616.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 52,748.604

Underlying: Common Stock, $0.10 par value · 884.017 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001071739-24-000223 · wk-form4_1734481978.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 23,000

F1 · balance_after: Owned by a revocable family trust, of which Mr. Samuels serves as a co-trustee.

SEC source: 0001020569-24-000238 · wk-form4_1728333889.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,362.224

Underlying: Common Stock · 38.167 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated common stock ("Common Stock") were sold in multiple transactions at prices ranging from $118.729 to $119.114, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-24-000232 · wk-form4_1727987125.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,324.057

Underlying: Common Stock · 241.938 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the Iron Mountain Incorporated board of directors as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated common stock ("Common Stock") were sold in multiple transactions at prices ranging from $118.869 to $118.789, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-24-000185 · wk-form4_1727903515.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,622.979

F1 · balance_after: Ownership includes 2,916 shares of restricted stock units subject to vesting requirements.

SEC source: 0000014272-24-000139 · wk-form4_1727905516.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,297.97

Underlying: Common Stock, $0.10 par value · 966.37 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-24-000192 · wk-form4_1720732598.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,082.119

Underlying: Common Stock · 305.25 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to the Reporting Person's quarterly cash compensation for services on the Iron Mountain Incorporated board of directors as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated common stock ("Common Stock") were sold in multiple transactions at prices ranging from $94.079 to $94.249, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001020569-24-000184 · wk-form4_1720489458.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,776.869

Underlying: Common Stock · 42.212 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F2 · shares: These shares give effect to dividends paid on Common Stock as if reinvested in Phantom Shares.

F3 · price: The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated common stock ("Common Stock") were sold in multiple transactions at prices ranging from $92.129 to $92.459, inclusive. The Reporting Person undertakes to provide Iron Mountain.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-24-000147 · wk-form4_1719956152.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,287.979

F1 · balance_after: Ownership includes 2,916 shares of restricted stock units subject to vesting requirements.

SEC source: 0000014272-24-000112 · wk-form4_1719955545.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 49,712.392

Underlying: Common Stock, $0.10 par value · 1,203.949 shares

Expires not disclosed

F1 · derivative.exercise_price: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.exercise_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F1 · derivative.expiration_date: Each Deferred Share Unit will be converted into a share of common stock upon settlement. The Deferred Share Units become settleable when the reporting person ceases to be a director or at a future date previously specified by the reporting person.

F2 · balance_after: Includes deferred compensation and dividends reinvested under the 1987 Deferred Compensation Plan for Non-Employee Directors.

SEC source: 0001020569-24-000142 · wk-form4_1717448821.xml · derivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,734.657

Underlying: Common Stock · 2,385 shares

Expires not disclosed

F1 · derivative.exercise_price: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan with respect to certain restricted stock units ("RSUs") received on May 30, 2024, which RSUs vest on the grant date, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.exercise_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan with respect to certain restricted stock units ("RSUs") received on May 30, 2024, which RSUs vest on the grant date, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

F1 · derivative.expiration_date: Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan with respect to certain restricted stock units ("RSUs") received on May 30, 2024, which RSUs vest on the grant date, the shares of phantom stock (the "Phantom Shares") will become payable in shares of Iron Mountain Incorporated common stock ("Common Stock") following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.

SEC source: 0001071739-24-000124 · wk-form4_1715897727.xml · nonDerivative · entry 1

Samuels Theodore R. II · CIK 0001688276 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 12,910.979

F1 · shares: This award includes 2,916 shares of restricted stock units which will vest in full on the earlier of May 14, 2025, and the date of the Registrant's next annual meeting of stockholders.