EX-99.3 4 q42023srpfinal.htm EX-99.3
Supplemental Financial Information Fourth Quarter 2023 investors.ironmountain.com

Table of Contents Section I - Q4 Earnings Press Release Q4 2023 Earnings Press Release 3 Section II - Financial Highlights and Organic Growth Financial and Operating Highlights 6 Organic Revenue Growth 7 Section III - Operational Metrics Global Storage Volume 8 Quarterly Operating Performance 9 Full Year Operating Performance 10 Section IV - Balance Sheets, Statements of Operations and Reconciliations Consolidated Balance Sheets 11 Quarterly Consolidated Statements of Operations 12 Full Year Consolidated Statements of Operations 13 Quarterly and Full Year Reconciliation of Net Income (Loss) to Adjusted EBITDA 14 Quarterly and Full Year Reconciliation of Reported Earnings per Share to Adjusted Earnings per Share 15 Quarterly Reconciliation of Net Income (Loss) to FFO and AFFO 16 Full Year Reconciliation of Net Income (Loss) to FFO and AFFO 18 Reconciliation of Net Income (Loss) to FFO and AFFO (Recast to updated calculation) 20 Section V - Storage and Service Reconciliation Quarterly Storage Rental and Service Business Detail 21 Full Year Storage and Service Business Detail 22 Section VI - Real Estate Metrics Global Real Estate Portfolio and Lease Obligations 23 Facility Lease Expirations 23 Section VII - Data Center Customer and Portfolio Metrics Data Center Customer Lease Expiration and Leasing Activity Summary 24 Data Center Operating Portfolio and Total Potential Capacity 25 Data Center Expansion and Development Activity 26 Section VIII - Capitalization and Debt Maturity Profile Capitalization 27 Total Borrowings Maturity Schedule 27 Debt Maturity Profile 27 Section IX - Capital Expenditures Quarterly and Full Year Capital Expenditures and Investments 28 Section X - Appendix and Definitions Appendix and Definitions 29 All figures except per share, megawatts (MW), kilowatts (kW), and facility counts in 000s unless noted All figures in reported dollars unless noted Figures may not foot due to rounding All figures for the quarter ended December 31, 2023 unless noted Unaudited investors.ironmountain.com Q4 2023 Supplemental Financial Information 2

Iron Mountain Reports Fourth Quarter and Full Year 2023 Results -- Net Income of $29 million; Achieves record quarterly and full year Revenue and Adjusted EBITDA -- -- Data Center: Leased 124 megawatts for the full year 2023 -- -- Issues Strong 2024 Guidance with Revenue Growth of 10-12% -- PORTSMOUTH, N.H. – February 22, 2024 – Iron Mountain Incorporated (NYSE: IRM), a global leader in information management services, announces financial results for the fourth quarter and full year 2023. The conference call / webcast details, earnings call presentation and supplemental financial information, which includes definitions of certain capitalized terms used in this release, are available on Iron Mountain’s Investor Relations website. Reconciliations of non-GAAP measures to the appropriate GAAP measures are included herein. "We are pleased to report outstanding performance in both the fourth quarter and the full year, again resulting in all-time record Revenue and Adjusted EBITDA," said William L. Meaney, President and CEO of Iron Mountain. "We are well positioned to continue our growth trajectory in 2024, which is reflected in our financial guidance for double digit revenue growth. Our Project Matterhorn initiative is propelling us on our growth journey, and our team's unwavering customer-first mindset continues to flourish as we grow our portfolio of products to meet our customers' needs. We are also pleased to confirm that our acquisition of Regency Technologies closed in early January; this acquisition continues to build on our leadership in Asset Lifecycle Management." Financial Performance Highlights for the Fourth Quarter and Full Year 2023 ($ in millions, except per share data) Three Months Ended Y/Y % Change Full Year Y/Y % Change 12/31/23 12/31/22 Reported $ Constant Fx 12/31/23 12/31/22 Reported $ Constant Fx Storage Rental Revenue $871 $769 13% 12% $3,371 $3,034 11% 11% Service Revenue $549 $510 8% 7% $2,109 $2,070 2% 2% Total Revenue $1,420 $1,279 11% 10% $5,480 $5,104 7% 8% Net Income $29 $126 (77)% $187 $562 (67)% Reported EPS $0.10 $0.42 (76)% $0.63 $1.90 (67)% Adjusted EPS $0.52 $0.43 21% $1.82 $1.79 2% Adjusted EBITDA $525 $472 11% 10% $1,962 $1,827 7% 8% Adjusted EBITDA Margin 37.0% 36.9% 10 bps 35.8% 35.8% — AFFO (Updated Calculation) $328 $299 10% $1,211 $1,151 5% AFFO per share (Updated Calculation) $1.11 $1.02 9% $4.12 $3.93 5% AFFO (Prior Calculation) $317 $287 10% $1,168 $1,110 5% AFFO per share (Prior Calculation) $1.07 $0.98 9% $3.97 $3.80 4% ___________________________________________________________________________________________________________ For details on our updated AFFO calculation, please see page 4. • Total reported revenues for the fourth quarter were $1.4 billion, compared with $1.3 billion in the fourth quarter of 2022, an increase of 11.0%. Excluding the impact of foreign currency exchange ("Fx"), total reported revenues increased 10.0% compared to the prior year, driven by a 12.0% increase in storage rental revenue. Service revenue growth increased 8.8% on a constant currency basis excluding the ALM business. For the full year, total reported revenues increased 7.4%, or 7.6% excluding the impact of Fx. • Net Income for the fourth quarter was $29.2 million, compared with $125.7 million in the fourth quarter of 2022. For the full year, net income was $187.3 million, compared with $562.1 million in 2022, primarily driven by higher levels of restructuring and other transformation costs, lower gains on asset recycling as compared to the full year of 2022, and the negative impact from changes in foreign exchange rates. • Adjusted EBITDA for the fourth quarter was $525.2 million, compared with $471.9 million in the fourth quarter of 2022, an increase of 11.3%. On a constant currency basis, Adjusted EBITDA increased by 10.3% in the fourth quarter, driven by the increase in storage rental revenue and data center commencements. On a constant currency basis, full year Adjusted EBITDA increased 7.5%. Section I - Q4 Earnings Press Release investors.ironmountain.com Q4 2023 Supplemental Financial Information 3

• FFO (Normalized) per share was $0.83 for the fourth quarter, compared with $0.74 in the fourth quarter of 2022. For the full year, FFO (Normalized) per share was $3.04, compared with $2.93 in 2022, or an increase of 3.8%. • AFFO was $327.6 million for the fourth quarter, compared with $298.5 million in the fourth quarter of 2022, an increase of 10%. For the full year, AFFO was $1.21 billion, compared with $1.15 billion in 2022, or an increase of 5%. Effective Q4 2023, our AFFO definition has been updated to exclude amortization of capitalized commissions. With this change, our calculation more accurately represents our funds available to support growth, and is more comparable to our peers, including those in the data center industry. The updated calculation has resulted in an $11.0 million increase to AFFO in the fourth quarter and a $43.4 million increase for the full year. For comparability to our previously issued financial guidance, please see the above table which includes the AFFO results based on both our updated and prior calculations. • AFFO per share was $1.11 for the fourth quarter, compared with $1.02 in the fourth quarter of 2022. For the full year, AFFO per share was $4.12, compared with $3.93 in 2022 or an increase of 5%. Effective Q4 2023, our AFFO definition has been updated to exclude amortization of capitalized commissions. With this change, our calculation is more comparable to our peers, including those in the data center industry. The updated calculation has resulted in a $0.04 increase to AFFO per share in the fourth quarter and a $0.15 increase to AFFO per share for the full year. For comparability to our previously issued financial guidance, please see the above table which includes the AFFO per share results based on both our updated and prior calculations. Dividend On February 22, 2024, Iron Mountain's Board of Directors declared a quarterly cash dividend of $0.65 per share for the first quarter. The first quarter 2024 dividend is payable on April 4, 2024, for shareholders of record on March 15, 2024. Guidance Iron Mountain issued full year 2024 guidance; details are summarized in the table below. 2024 Guidance(1) ($ in millions, except per share data) 2024 Guidance Y/Y % Change at Midpoint Total Revenue $6,000 - $6,150 11% Adjusted EBITDA $2,175 - $2,225 12% AFFO $1,300 - $1,335 9% AFFO Per Share $4.39 - $4.51 8% (1) Iron Mountain does not provide a reconciliation of non-GAAP measures that it discusses as part of its annual guidance or long term outlook because certain significant information required for such reconciliation is not available without unreasonable efforts or at all, including, most notably, the impact of exchange rates on Iron Mountain’s transactions, loss or gain related to the disposition of real estate and other income or expense. Without this information, Iron Mountain does not believe that a reconciliation would be meaningful. AFFO and AFFO per share are presented based on our updated calculation, and growth is calculated on a comparable basis. About Iron Mountain Iron Mountain Incorporated (NYSE: IRM) is a global leader in information management services. Founded in 1951 and trusted by more than 240,000 customers worldwide, Iron Mountain serves to protect and elevate the power of our customers’ work. Through a range of offerings including digital transformation, data centers, secure records storage, information management, asset lifecycle management, secure destruction and art storage and logistics, Iron Mountain helps businesses bring light to their dark data, enabling customers to unlock value and intelligence from their stored digital and physical assets at speed and with security, while helping them meet their environmental goals. To learn more about Iron Mountain, please visit: www.IronMountain.com and follow @IronMountain on X (formerly Twitter) and LinkedIn. Section I - Q4 Earnings Press Release investors.ironmountain.com Q4 2023 Supplemental Financial Information 4

Safe Harbor Statement Under the Private Securities Litigation Reform Act of 1995: We have made statements in this press release that constitute "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995 and other securities laws. These forward-looking statements concern our current expectations regarding our future results from operations, economic performance, financial condition, goals, strategies, investment objectives, plans and achievements. These forward-looking statements are subject to various known and unknown risks, uncertainties and other factors, and you should not rely upon them except as statements of our present intentions and of our present expectations, which may or may not occur. When we use words such as “believes”, “expects”, “anticipates”, “estimates”, “plans”, “intends”, “pursue”, “will” or similar expressions, we are making forward-looking statements. Although we believe that our forward-looking statements are based on reasonable assumptions, our expected results may not be achieved, and actual results may differ materially from our expectations. In addition, important factors that could cause actual results to differ from expectations include, among others: (i) our ability or inability to execute our strategic growth plan, including our ability to invest according to plan, grow our businesses (including through joint ventures), incorporate alternative technologies into our offerings, achieve satisfactory returns on new product offerings, continue our revenue management, expand and manage our global operations, complete acquisitions on satisfactory terms, integrate acquired companies efficiently and transition to more sustainable sources of energy; (ii) changes in customer preferences and demand for our storage and information management services, including as a result of the shift from paper and tape storage to alternative technologies that require less physical space; (iii) the impact of our distribution requirements on our ability to execute our business plan; (iv) the costs of complying with and our ability to comply with laws, regulations and customer requirements, including those relating to data privacy and cybersecurity issues, as well as fire and safety and environmental standards; (v) the impact of attacks on our internal information technology (“IT”) systems, including the impact of such incidents on our reputation and ability to compete and any litigation or disputes that may arise in connection with such incidents; (vi) our ability to fund capital expenditures; (vii) our ability to remain qualified for taxation as a real estate investment trust for United States federal income tax purposes (“REIT”); (viii) changes in the political and economic environments in the countries in which we operate and changes in the global political climate; (ix) our ability to raise debt or equity capital and changes in the cost of our debt; (x) our ability to comply with our existing debt obligations and restrictions in our debt instruments; (xi) the impact of service interruptions or equipment damage and the cost of power on our data center operations; (xii) the cost or potential liabilities associated with real estate necessary for our business; (xiii) unexpected events, including those resulting from climate change or geopolitical events, could disrupt our operations and adversely affect our reputation and results of operations; (xiv) failures to implement and manage new IT systems; (xv) other trends in competitive or economic conditions affecting our financial condition or results of operations not presently contemplated; and (xvi) the other risks described in our periodic reports filed with the SEC, including under the caption “Risk Factors” in Part I, Item 1A of our Annual Report. Except as required by law, we undertake no obligation to update any forward-looking statements appearing in this release. Reconciliation of Non-GAAP Measures Throughout this release, Iron Mountain discusses (1) Adjusted EBITDA, (2) Adjusted EPS, (3) FFO (Nareit), (4) FFO (Normalized), and (5) AFFO. These measures do not conform to accounting principles generally accepted in the United States (“GAAP”). These non-GAAP measures are supplemental metrics designed to enhance our disclosure and to provide additional information that we believe to be important for investors to consider in addition to, but not as a substitute for, other measures of financial performance reported in accordance with GAAP, such as operating income, net income (loss) attributable to Iron Mountain Incorporated or cash flows from operating activities (as determined in accordance with GAAP). The reconciliation of these measures to the appropriate GAAP measure, as required by Regulation G under the Securities Exchange Act of 1934, as amended, and their definitions are included later in this release. Investor Relations Contacts: Gillian Tiltman Erika Crabtree SVP, Head of Investor Relations Manager, Investor Relations Gillian.Tiltman@ironmountain.com Erika.Crabtree@ironmountain.com (617) 286-4881 (617) 535-2845 Section I - Q4 Earnings Press Release investors.ironmountain.com Q4 2023 Supplemental Financial Information 5

Financial Highlights Q4 2023 Q3 2023 Q2 2023 Q1 2023 Q4 2022 Storage Rental Revenue $871,144 $858,656 $830,756 $810,089 $769,457 Service Revenue $548,685 $529,519 $527,180 $504,260 $509,592 Total Revenues $1,419,829 $1,388,175 $1,357,936 $1,314,349 $1,279,049 Adjusted EBITDA $525,249 $499,962 $475,658 $460,808 $471,923 Adjusted EBITDA Margin 37.0 % 36.0 % 35.0 % 35.1 % 36.9 % Net Income (Loss) Attributable to Iron Mountain Incorporated $28,482 $91,043 $114 $64,595 $122,437 Reported EPS - Fully Diluted $0.10 $0.31 $0.00 $0.22 $0.42 Adjusted EPS $0.52 $0.45 $0.40 $0.42 $0.43 FFO (Normalized) $246,005 $223,080 $208,113 $207,392 $216,182 FFO (Normalized) per Share $0.83 $0.76 $0.71 $0.71 $0.74 AFFO (Updated Calculation) $327,634 $301,201 $287,090 $295,242 $298,523 AFFO per Share (Updated Calculation) $1.11 $1.02 $0.98 $1.01 $1.02 TTM AFFO Payout Ratio (Updated Calculation) 61.6 % 62.2 % 61.5 % 61.7 % 62.9 % AFFO (Prior Calculation) $316,588 $290,136 $277,029 $284,000 $286,791 AFFO per Share (Prior Calculation) $1.07 $0.99 $0.94 $0.97 $0.98 TTM AFFO Payout Ratio (Prior Calculation) 63.9 % 64.6 % 63.9 % 64.1 % 65.2 % Dividend per Share $0.65 $0.65 $0.62 $0.62 $0.62 Weighted Average Common Shares Outstanding - Diluted 295,014 294,269 293,527 293,049 292,892 Net Lease-Adjusted Leverage Ratio 5.1x 5.1x 5.1x 5.1x 5.1x Operating Highlights Q4 2023 Q3 2023 Q2 2023 Q1 2023 Q4 2022 Organic Storage Rental Revenue Growth 10.4 % 9.7 % 10.8 % 11.1 % 11.0 % Organic Service Revenue Growth 6.2 % (0.6) % (1.4) % 2.0 % 11.8 % Total Volume - Storage 731,541 731,263 730,767 730,136 729,284 Storage Facility Capacity Utilization 79.6 % 79.4 % 79.6 % 79.5 % 79.3 % Records Management Retention Rate 92.9 % 93.0 % 92.8 % 93.0 % 93.3 % Storage Revenue / Sq. Ft. $9.15 $9.00 $8.78 $8.64 $8.34 Storage NOI / Sq. Ft. $7.37 $7.23 $7.10 $7.00 $6.84 Data Center: Leasable Megawatts 255.4 225.2 221.2 206.9 191.6 Leased % - Stabilized 95.4 % 94.6 % 94.7 % 94.3 % 92.6 % Leased % - Total 93.3 % 91.8 % 92.2 % 92.2 % 91.6 % Kilowatts Leased - New/Expansion 4,535 65,355 2,690 51,770 13,657 Churn 1.7 % 1.0 % 1.4 % 1.5 % 0.2 % Number of Facilities 26 24 24 24 21 Number of Markets 21 21 19 19 19 Section II - Financial Highlights and Organic Growth investors.ironmountain.com Q4 2023 Supplemental Financial Information 6

Organic Revenue Growth (1) Q4 2023 Q3 2023 Full Year 2023 Reported Constant Currency Organic Revenue Reported Constant Currency Organic Revenue Reported Constant Currency Organic Revenue Storage Rental 13.2% 12.0% 10.4% 12.9% 11.6% 9.7% 11.1% 11.2% 10.5% Service 7.7% 6.8% 6.2% 0.6% (0.1)% (0.6)% 1.9% 2.2% 1.6% Total Revenues 11.0% 10.0% 8.7% 7.9% 6.8% 5.5% 7.4% 7.6% 6.9% Total Organic Revenue Growth 10.0% 12.8% 14.1% 11.3% 7.5% 5.7% 5.5% 8.7% Q1 2022 Q2 2022 Q3 2022 Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 0.0% 4.0% 8.0% 12.0% 16.0% Organic Storage Rental Revenue Growth 6.8% 8.2% 9.7% 11.0% 11.1% 10.8% 9.7% 10.4% Q1 2022 Q2 2022 Q3 2022 Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% Organic Service Revenue Growth 16.1% 21.1% 21.8% 11.8% 2.0% (1.4)% (0.6)% 6.2% Q1 2022 Q2 2022 Q3 2022 Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 (10.0)% 0.0% 10.0% 20.0% 30.0% (1) Constant Currency and excluding impact from business acquisitions and divestitures. Section II - Financial Highlights and Organic Growth investors.ironmountain.com Q4 2023 Supplemental Financial Information 7

Global Storage Volume Global RIM Corporate and Other Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 500,000 550,000 600,000 650,000 700,000 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 Global RIM 711,549 722,582 721,945 723,331 725,665 727,496 724,480 724,926 725,510 (1) 725,907 726,048 Corporate and Other 4,223 4,250 4,301 4,322 4,336 4,715 4,804 5,210 5,256 5,356 5,493 Total Volume - Storage 715,772 726,831 726,246 727,653 730,002 732,211 729,284 730,136 730,767 731,263 731,541 Business acquisitions during the quarter (2) 5,020 10,743 — — — 143 — — — — — (1) On June 29, 2023, we acquired 100% interest in Clutter Intermediate, Inc. and control of all assets of the related Clutter joint venture, of which we had a preexisting relationship. The volume associated with this business both prior and subsequent to our acquisition is substantially consistent. (2) Volume acquired through acquisition in the quarter; this is included in Total Storage Volume. Section III - Operational Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 8

Quarterly Operating Performance Y/Y % Change Q4 2023 Q3 2023 Q4 2022 Reported Constant Currency Organic Growth (1) Global RIM Business Storage Rental $723,112 $719,560 $656,721 10.1% 9.0% 8.1% Service 469,619 463,092 427,924 9.7% 8.9% 8.9% Total Revenues $1,192,731 $1,182,652 $1,084,645 10.0% 9.0% 8.5% Adjusted EBITDA $533,643 $516,548 $485,563 Adjusted EBITDA Margin 44.7 % 43.7 % 44.8 % Global Data Center Business Storage Rental $131,986 $123,655 $98,661 33.8% 31.7% 26.0% Service 5,167 3,880 5,081 1.7% (0.7)% (0.3)% Total Revenues $137,153 $127,535 $103,742 32.2% 30.1% 24.7% Adjusted EBITDA $58,285 $53,216 $48,678 Adjusted EBITDA Margin 42.5 % 41.7 % 46.9 % Corporate and Other Storage Rental $16,046 $15,441 $14,075 14.0% 13.0% 6.5% Service 73,899 62,547 76,587 (3.5)% (4.2)% (9.4)% Total Revenues $89,946 $77,988 $90,661 (0.8)% (1.5)% (6.9)% Adjusted EBITDA $(66,679) $(69,802) $(62,318) Total Consolidated Storage Rental $871,144 $858,656 $769,457 13.2% 12.0% 10.4% Service 548,685 529,519 509,592 7.7% 6.8% 6.2% Total Revenues $1,419,829 $1,388,175 $1,279,049 11.0% 10.0% 8.7% Adjusted EBITDA $525,249 $499,962 $471,923 Adjusted EBITDA Margin 37.0 % 36.0 % 36.9 % (1) Constant Currency and excluding impact from business acquisitions and divestitures. Section III - Operational Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 9

Full Year Operating Performance Y/Y % Change Full Year 2023 Full Year 2022 Reported Constant Currency Organic Growth (1) Global RIM Business Storage Rental $2,834,352 $2,606,721 8.7% 9.0% 8.6% Service 1,827,424 1,688,394 8.2% 8.6% 9.1% Total Revenues $4,661,776 $4,295,115 8.5% 8.8% 8.8% Adjusted EBITDA $2,027,037 $1,887,589 Adjusted EBITDA Margin 43.5 % 43.9 % Global Data Center Business Storage Rental $474,066 $372,208 27.4% 26.4% 23.4% Service 20,960 28,917 (27.5)% (28.2)% (27.9)% Total Revenues $495,026 $401,125 23.4% 22.4% 19.7% Adjusted EBITDA $215,945 $175,622 Adjusted EBITDA Margin 43.6 % 43.8 % Corporate and Other Storage Rental $62,227 $55,094 12.9% 12.7% 8.1% Service 261,260 352,240 (25.8)% (25.8)% (31.1)% Total Revenues $323,487 $407,334 (20.6)% (20.6)% (25.8)% Adjusted EBITDA $(281,305) $(236,154) Total Consolidated Storage Rental $3,370,645 $3,034,023 11.1% 11.2% 10.5% Service 2,109,644 2,069,551 1.9% 2.2% 1.6% Total Revenues $5,480,289 $5,103,574 7.4% 7.6% 6.9% Adjusted EBITDA $1,961,677 $1,827,057 Adjusted EBITDA Margin 35.8 % 35.8 % (1) Constant Currency and excluding impact from business acquisitions and divestitures. Section III - Operational Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 10

Consolidated Balance Sheets 12/31/2023 12/31/2022 ASSETS Current Assets: Cash and Cash Equivalents $222,789 $141,797 Accounts Receivable, Net 1,259,826 1,174,915 Prepaid Expenses and Other 252,930 230,433 Total Current Assets $1,735,545 $1,547,145 Property, Plant and Equipment: Property, Plant and Equipment $10,373,989 $9,025,765 Less: Accumulated Depreciation (4,059,120) (3,910,321) Property, Plant and Equipment, Net $6,314,869 $5,115,444 Other Assets, Net: Goodwill $5,017,912 $4,882,734 Customer and Supplier Relationships and Other Intangible Assets 1,279,800 1,423,145 Operating Lease Right-of-Use Assets 2,696,024 2,583,704 Other 429,652 588,342 Total Other Assets, Net $9,423,388 $9,477,925 Total Assets $17,473,802 $16,140,514 LIABILITIES AND EQUITY Current Liabilities: Current Portion of Long-term Debt $120,670 $87,546 Accounts Payable 539,594 469,198 Accrued Expenses and Other Current Liabilities 1,250,259 1,031,910 Deferred Revenue 325,665 328,910 Total Current Liabilities $2,236,188 $1,917,564 Long-term Debt, Net of Current Portion 11,812,500 10,481,449 Long-term Operating Lease Liabilities, Net of Current Portion 2,562,394 2,429,167 Other Long-term Liabilities 237,590 317,376 Deferred Income Taxes 235,410 263,005 Redeemable Noncontrolling Interests 177,947 95,160 Total Long-term Liabilities $15,025,841 $13,586,157 Total Liabilities $17,262,029 $15,503,721 Equity Total Equity $211,773 $636,793 Total Liabilities and Equity $17,473,802 $16,140,514 Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 11

Quarterly Consolidated Statements of Operations Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change Revenues: Storage Rental $871,144 $858,656 1.5 % $769,457 13.2 % Service 548,685 529,519 3.6 % 509,592 7.7 % Total Revenues $1,419,829 $1,388,175 2.3 % $1,279,049 11.0 % Operating Expenses: Cost of Sales (excluding Depreciation and Amortization) $601,329 $592,201 1.5 % $539,982 11.4 % Selling, General and Administrative 314,932 315,030 — 279,161 12.8 % Depreciation and Amortization 199,941 198,757 0.6 % 190,649 4.9 % Acquisition and Integration Costs 12,860 9,909 29.8 % 9,653 33.2 % Restructuring and Other Transformation 53,853 38,861 38.6 % 38,551 39.7 % Loss (Gain) on Disposal/Write-Down of PP&E, Net 6,157 (4,416) n/a (27,144) (122.7) % Total Operating Expenses $1,189,072 $1,150,342 3.4 % $1,030,852 15.3 % Operating Income (Loss) $230,757 $237,833 (3.0) % $248,197 (7.0) % Interest Expense, Net 151,784 152,801 (0.7) % 136,748 11.0 % Other Expense (Income), Net 40,761 (16,271) n/a (31,597) n/a Net Income (Loss) Before Provision (Benefit) for Income Taxes $38,212 $101,303 (62.3) % $143,046 (73.3) % Provision (Benefit) for Income Taxes 9,018 9,912 (9.0) % 17,392 (48.1) % Net Income (Loss) $29,194 $91,391 (68.1) % $125,654 (76.8) % Less: Net Income (Loss) Attributable to Noncontrolling Interests 712 348 104.6 % 3,216 (77.9) % Net Income (Loss) Attributable to Iron Mountain Incorporated $28,482 $91,043 (68.7) % $122,437 (76.7) % Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated: Basic $0.10 $0.31 (67.7) % $0.42 (76.2) % Diluted $0.10 $0.31 (67.7) % $0.42 (76.2) % Weighted Average Common Shares Outstanding - Basic 292,328 292,148 0.1 % 291,227 0.4 % Weighted Average Common Shares Outstanding - Diluted 295,014 294,269 0.3 % 292,892 0.7 % Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 12

Full Year Consolidated Statements of Operations Full Year 2023 Full Year 2022 % Change Revenues: Storage Rental $3,370,645 $3,034,023 11.1 % Service 2,109,644 2,069,551 1.9 % Total Revenues $5,480,289 $5,103,574 7.4 % Operating Expenses: Cost of Sales (excluding Depreciation and Amortization) $2,357,800 $2,189,120 7.7 % Selling, General and Administrative 1,236,287 1,140,577 8.4 % Depreciation and Amortization 776,159 727,595 6.7 % Acquisition and Integration Costs 25,875 47,746 (45.8) % Restructuring and Other Transformation 175,215 41,933 n/a (Gain) Loss on Disposal/Write-Down of PP&E, Net (12,825) (93,268) (86.2) % Total Operating Expenses $4,558,511 $4,053,703 12.5 % Operating Income (Loss) $921,778 $1,049,871 (12.2) % Interest Expense, Net 585,932 488,014 20.1 % Other Expense (Income), Net 108,640 (69,781) n/a Net Income (Loss) Before Provision (Benefit) for Income Taxes $227,206 $631,638 (64.0) % Provision (Benefit) for Income Taxes 39,943 69,489 (42.5) % Net Income (Loss) $187,263 $562,149 (66.7) % Less: Net Income (Loss) Attributable to Noncontrolling Interests 3,029 5,168 (41.4) % Net Income (Loss) Attributable to Iron Mountain Incorporated $184,234 $556,981 (66.9) % Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated: Basic $0.63 $1.92 (67.2) % Diluted $0.63 $1.90 (66.8) % Weighted Average Common Shares Outstanding - Basic 291,936 290,812 0.4 % Weighted Average Common Shares Outstanding - Diluted 293,965 292,444 0.5 % Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 13

Quarterly Reconciliation of Net Income (Loss) to Adjusted EBITDA Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change Net Income $29,194 $91,391 (68.1) % $125,654 (76.8) % Add / (Deduct): Interest Expense, Net 151,784 152,801 (0.7) % 136,748 11.0 % Provision (Benefit) for Income Taxes 9,018 9,912 (9.0) % 17,392 (48.1) % Depreciation and Amortization 199,941 198,757 0.6 % 190,649 4.9 % Acquisition and Integration Costs 12,860 9,909 29.8 % 9,653 33.2 % Restructuring and Other Transformation 53,853 38,861 38.6 % 38,551 39.7 % Loss (Gain) on Disposal/Write-Down of PP&E, Net (Including Real Estate) 6,157 (4,416) n/a (27,144) (122.7) % Other Expense (Income), Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures 40,332 (17,626) n/a (34,455) n/a Stock-Based Compensation Expense 20,604 18,313 12.5 % 10,938 88.4 % Our Share of Adjusted EBITDA Reconciling Items from our Unconsolidated Joint Ventures 1,506 2,060 (26.9) % 3,937 (61.7) % Adjusted EBITDA $525,249 $499,962 5.1 % $471,923 11.3 % Full Year Reconciliation of Net Income (Loss) to Adjusted EBITDA Full Year 2023 Full Year 2022 % Change Net Income $187,263 $562,149 (66.7) % Add / (Deduct): Interest Expense, Net 585,932 488,014 20.1 % Provision (Benefit) for Income Taxes 39,943 69,489 (42.5) % Depreciation and Amortization 776,159 727,595 6.7 % Acquisition and Integration Costs 25,875 47,746 (45.8) % Restructuring and Other Transformation 175,215 41,933 n/a (Gain) Loss on Disposal/Write-Down of PP&E, Net (Including Real Estate) (12,825) (93,268) (86.2) % Other Expense (Income), Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures 98,891 (83,268) n/a Stock-Based Compensation Expense 73,799 56,861 29.8 % Our Share of Adjusted EBITDA Reconciling Items from our Unconsolidated Joint Ventures 11,425 9,806 16.5 % Adjusted EBITDA $1,961,677 $1,827,057 7.4 % Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 14

Quarterly Reconciliation of Reported Earnings per Share to Adjusted Earnings per Share Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change Reported EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $0.10 $0.31 (67.7) % $0.42 (76.2) % Add / (Deduct): Acquisition and Integration Costs 0.04 0.03 33.3 % 0.03 33.3 % Restructuring and Other Transformation 0.18 0.13 38.5 % 0.13 38.5 % Loss (Gain) on Disposal/Write-Down of PP&E, Net 0.02 (0.02) n/a (0.09) (122.2) % Other Expense (Income), Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures 0.14 (0.06) n/a (0.12) n/a Stock-Based Compensation Expense 0.07 0.06 16.7 % 0.04 75.0 % Non-Cash Amortization Related to Derivative Instruments 0.01 0.02 (50.0) % 0.03 (66.7) % Tax Impact of Reconciling Items and Discrete Tax Items (1) (0.04) (0.03) 33.3 % (0.02) 100.0 % Net Income Attributable to Noncontrolling Interests — — n/a 0.01 (100.0) % Adjusted EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $0.52 $0.45 15.6 % $0.43 20.9 % Full Year Reconciliation of Reported Earnings per Share to Adjusted Earnings per Share Full Year 2023 Full Year 2022 % Change Reported EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $0.63 $1.90 (66.8) % Add / (Deduct): Acquisition and Integration Costs 0.09 0.16 (43.8) % Restructuring and Other Transformation 0.60 0.14 n/a Amortization Related to the Write-Off of Certain Customer Relationship Intangible Assets — 0.02 (100.0) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (0.04) (0.31) (87.1) % Other Expense (Income), Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures 0.34 (0.28) n/a Stock-Based Compensation Expense 0.25 0.19 31.6 % Non-Cash Amortization Related to Derivative Instruments 0.07 0.03 133.3 % Tax Impact of Reconciling Items and Discrete Tax Items (1) (0.12) (0.08) 50.0 % Net Income Attributable to Noncontrolling Interests 0.01 0.02 (50.0) % Adjusted EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $1.82 $1.79 1.7 % (1) The difference between our effective tax rates and our structural tax rate (or adjusted effective tax rates) for the three and twelve months ended December 31, 2023 and 2022 is primarily due to (i) the reconciling items above, which impact our reported net income (loss) before provision (benefit) for income taxes but have an insignificant impact on our reported provision (benefit) for income taxes and (ii) other discrete tax items. Our structural tax rate for purposes of the calculation of Adjusted EPS for the quarters and years ended December 31, 2023 and 2022 was 12.3% and 15.2%, respectively, and the quarter ended September 30, 2023 was 13.3%. The Tax Impact of Reconciling Items and Discrete Tax Items was calculated using the current quarter’s estimate of the annual structural tax rate. This may result in the current period adjustment plus prior reported quarterly adjustments not summing to the year to date adjustment. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 15

Quarterly Reconciliation of Net Income (Loss) to FFO and AFFO Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change Net Income $29,194 $91,391 (68.1) % $125,654 (76.8) % Add / (Deduct): Real Estate Depreciation (1) 83,928 80,430 4.4 % 78,902 6.4 % Loss (Gain) on Sale of Real Estate, Net of Tax 193 750 (74.3) % (29,629) (100.7) % Data Center Lease-Based Intangible Assets Amortization (2) 3,804 7,482 (49.2) % 5,106 (25.5) % Our Share of FFO (Nareit) Reconciling Items from our Unconsolidated Joint Ventures 853 679 25.6 % — — FFO (Nareit) $117,972 $180,732 (34.7) % $180,033 (34.5) % Add / (Deduct): Acquisition and Integration Costs 12,860 9,909 29.8 % 9,653 33.2 % Restructuring and Other Transformation 53,853 38,861 38.6 % 38,551 39.7 % Loss (Gain) on Disposal/Write-Down of PP&E, Net (Excluding Real Estate) 6,290 (5,116) n/a 2,138 194.3 % Other Expense (Income), Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures 40,332 (17,626) n/a (34,455) n/a Stock-Based Compensation Expense 20,604 18,313 12.5 % 10,938 88.4 % Non-Cash Amortization Related to Derivative Instruments 4,176 5,270 (20.8) % 9,100 (54.1) % Real Estate Financing Lease Depreciation 3,022 3,001 0.7 % 2,970 1.8 % Tax Impact of Reconciling Items and Discrete Tax Items (3) (13,050) (10,220) 27.7 % (5,043) 158.8 % Our Share of FFO (Normalized) Reconciling Items from our Unconsolidated Joint Ventures (56) (44) 27.3 % 2,297 (102.4) % FFO (Normalized) $246,005 $223,080 10.3 % $216,182 13.8 % Per Share Amounts (Fully Diluted Shares): FFO (Nareit) $0.40 $0.61 (34.4) % $0.61 (34.4) % FFO (Normalized) $0.83 $0.76 9.2 % $0.74 12.2 % Weighted Average Common Shares Outstanding - Basic 292,328 292,148 0.1 % 291,227 0.4 % Weighted Average Common Shares Outstanding - Diluted 295,014 294,269 0.3 % 292,892 0.7 % (1) Includes depreciation expense related to owned real estate assets (land improvements, buildings, building improvements, leasehold improvements and racking), excluding depreciation related to real estate financing leases. (2) Includes amortization expense for Data Center In-Place Lease Intangible Assets and Data Center Tenant Relationship Intangible Assets. (3) Represents the tax impact of (i) the reconciling items above, which impacts our reported net income (loss) before provision (benefit) for income taxes but have an insignificant impact on our reported provision (benefit) for income taxes and (ii) other discrete tax items. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 16

Quarterly Reconciliation of Net Income (Loss) to FFO and AFFO (Continued) Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change FFO (Normalized) $246,005 $223,080 10.3 % $216,182 13.8 % Add / (Deduct): Non-Real Estate Depreciation 51,572 49,500 4.2 % 46,486 10.9 % Amortization Expense (1) 57,613 58,344 (1.3) % 57,186 0.7 % Amortization of Deferred Financing Costs 3,278 5,485 (40.2) % 4,508 (27.3) % Revenue Reduction Associated with Amortization of Customer Inducements and Above- and Below-Market Leases 1,829 1,715 6.6 % 2,587 (29.3) % Non-Cash Rent Expense (Income) 4,982 6,119 (18.6) % 6,024 (17.3) % Reconciliation to Normalized Cash Taxes 7,090 (8,364) (184.8) % 916 n/a Our Share of AFFO Reconciling Items from our Unconsolidated Joint Ventures 181 182 (0.5) % 974 (81.4) % Less: Recurring Capital Expenditures 44,916 34,861 28.8 % 36,340 23.6 % AFFO $327,634 $301,201 8.8 % $298,523 9.8 % Per Share Amounts (Fully Diluted Shares): AFFO Per Share $1.11 $1.02 8.8 % $1.02 8.8 % Weighted Average Common Shares Outstanding - Basic 292,328 292,148 0.1 % 291,227 0.4 % Weighted Average Common Shares Outstanding - Diluted 295,014 294,269 0.3 % 292,892 0.7 % (1) Includes customer and supplier relationship value, intake costs, acquisition of customer relationships, capitalized commissions and other intangibles. Effective Q4 2023, our AFFO definition has been updated to exclude the amortization of capitalized commissions. Amortization expense of capitalized commissions was $11.0M and $11.7M for quarters ended December 31, 2023 and 2022 respectively, and $11.1M for quarter ended September 30, 2023. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 17

Full Year Reconciliation of Net Income (Loss) to FFO and AFFO Full Year 2023 Full Year 2022 % Change Net Income $187,263 $562,149 (66.7) % Add / (Deduct): Real Estate Depreciation (1) 322,045 307,895 4.6 % (Gain) Loss on Sale of Real Estate, Net of Tax (16,656) (94,059) (82.3) % Data Center Lease-Based Intangible Assets Amortization (2) 22,322 16,955 31.7 % Our Share of FFO (Nareit) Reconciling Items from our Unconsolidated Joint Ventures 2,226 — n/a FFO (Nareit) $517,200 $792,940 (34.8) % Add / (Deduct): Acquisition and Integration Costs 25,875 47,746 (45.8) % Restructuring and Other Transformation 175,215 41,933 n/a Loss (Gain) on Disposal/Write-Down of PP&E, Net (Excluding Real Estate) 4,307 1,564 175.4 % Other Expense (Income), Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures 98,891 (83,268) n/a Stock-Based Compensation Expense 73,799 56,861 29.8 % Non-Cash Amortization Related to Derivative Instruments 21,097 9,100 131.8 % Real Estate Financing Lease Depreciation 12,019 13,197 (8.9) % Tax Impact of Reconciling Items and Discrete Tax Items (3) (35,307) (25,190) 40.2 % Our Share of FFO (Normalized) Reconciling Items from our Unconsolidated Joint Ventures (374) 2,874 (113.0) % FFO (Normalized) $892,722 $857,757 4.1 % Per Share Amounts (Fully Diluted Shares): FFO (Nareit) $1.76 $2.71 (35.1) % FFO (Normalized) $3.04 $2.93 3.8 % Weighted Average Common Shares Outstanding - Basic 291,936 290,812 0.4 % Weighted Average Common Shares Outstanding - Diluted 293,965 292,444 0.5 % (1) Includes depreciation expense related to owned real estate assets (land improvements, buildings, building improvements, leasehold improvements and racking), excluding depreciation related to real estate financing leases. (2) Includes amortization expense for Data Center In-Place Lease Intangible Assets and Data Center Tenant Relationship Intangible Assets. (3) Represents the tax impact of (i) the reconciling items above, which impact our reported net income (loss) before provision (benefit) for income taxes but have an insignificant impact on our reported provision (benefit) from income taxes and (ii) other discrete tax items. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 18

Full Year Reconciliation of Net Income (Loss) to FFO and AFFO (continued) Full Year 2023 Full Year 2022 % Change FFO (Normalized) $892,722 $857,757 4.1 % Add / (Deduct): Non-Real Estate Depreciation 191,785 157,892 21.5 % Amortization Expense (1) 227,987 231,656 (1.6) % Amortization of Deferred Financing Costs 16,859 18,044 (6.6) % Revenue Reduction Associated with Amortization of Customer Inducements and Above- and Below-Market Leases 7,036 8,119 (13.3) % Non-Cash Rent Expense (Income) 25,140 19,056 31.9 % Reconciliation to Normalized Cash Taxes (14,826) (3,622) n/a Our Share of AFFO Reconciling Items from our Unconsolidated Joint Ventures 4,868 4,135 17.7 % Less: Recurring Capital Expenditures 140,406 142,496 (1.5) % AFFO $1,211,165 $1,150,541 5.3 % Per Share Amounts (Fully Diluted Shares): AFFO Per Share $4.12 $3.93 4.8 % Weighted Average Common Shares Outstanding - Basic 291,936 290,812 0.4 % Weighted Average Common Shares Outstanding - Diluted 293,965 292,444 0.5 % (1) Includes customer and supplier relationship value, intake costs, acquisition of customer relationships, capitalized commissions and other intangibles. Effective Q4 2023, our AFFO definition has been updated to exclude the amortization of capitalized commissions. Amortization expense of capitalized commissions was $43.4M and $40.6M for full year 2023 and 2022 respectively. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 19

Reconciliation of Net Income (Loss) to FFO and AFFO (Recast to Updated Calculation) Full Year 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 Full Year 2023 Net Income $562,149 $65,535 $1,143 $91,391 $29,194 $187,263 Add / (Deduct): Real Estate Depreciation (1) 307,895 76,129 81,558 80,430 83,928 322,045 (Gain) Loss on Sale of Real Estate, Net of Tax (94,059) (15,746) (1,853) 750 193 (16,656) Data Center Lease-Based Intangible Assets Amortization (2) 16,955 6,129 4,907 7,482 3,804 22,322 Our Share of FFO (Nareit) Reconciling Items from our Unconsolidated Joint Ventures — 132 562 679 853 2,226 FFO (Nareit) $792,940 $132,179 $86,317 $180,732 $117,972 $517,200 Add / (Deduct): Acquisition and Integration Costs 47,746 1,595 1,511 9,909 12,860 25,875 Restructuring and Other Transformation 41,933 36,913 45,588 38,861 53,853 175,215 Loss (Gain) on Disposal/Write-Down of PP&E, Net (Excluding Real Estate) 1,564 4,550 (1,417) (5,116) 6,290 4,307 Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (83,268) 17,491 58,694 (17,626) 40,332 98,891 Stock-Based Compensation Expense 56,861 12,509 22,373 18,313 20,604 73,799 Non-Cash Amortization Related to Derivative Instruments 9,100 5,834 5,817 5,270 4,176 21,097 Real Estate Financing Lease Depreciation 13,197 2,988 3,008 3,001 3,022 12,019 Tax Impact of Reconciling Items and Discrete Tax Items (3) (25,190) (6,893) (13,278) (10,220) (13,050) (35,307) Our Share of FFO (Normalized) Reconciling Items from our Unconsolidated Joint Ventures 2,874 226 (500) (44) (56) (374) FFO (Normalized) $857,757 $207,392 $208,113 $223,080 $246,005 $892,722 Add / (Deduct): Non-Real Estate Depreciation 157,892 40,948 49,765 49,500 51,572 191,785 Amortization Expense 231,656 55,899 56,131 58,344 57,613 227,987 Amortization of Deferred Financing Costs 18,044 4,332 3,763 5,485 3,278 16,859 Revenue Reduction Associated with Amortization of Customer Inducements and Above- and Below-Market Leases 8,119 1,760 1,732 1,715 1,829 7,036 Non-Cash Rent Expense (Income) 19,056 7,436 6,603 6,119 4,982 25,140 Reconciliation to Normalized Cash Taxes (3,622) 3,157 (8,575) (8,364) 7,090 (14,826) Our Share of AFFO Reconciling Items from our Unconsolidated Joint Ventures 4,135 1,981 2,525 182 181 4,868 Less: Recurring Capital Expenditures 142,496 27,663 32,967 34,861 44,916 140,406 AFFO $1,150,541 $295,242 $287,090 $301,201 $327,634 $1,211,165 Per Share Amounts (Fully Diluted Shares): FFO (Nareit) $2.71 $0.45 $0.29 $0.61 $0.40 $1.76 FFO (Normalized) $2.93 $0.71 $0.71 $0.76 $0.83 $3.04 AFFO Per Share $3.93 $1.01 $0.98 $1.02 $1.11 $4.12 Weighted Average Common Shares Outstanding - Basic 290,812 291,442 291,825 292,148 292,328 291,936 Weighted Average Common Shares Outstanding - Diluted 292,444 293,049 293,527 294,269 295,014 293,965 Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q4 2023 Supplemental Financial Information 20

Quarterly Storage Rental and Service Business Detail Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change Storage Rental Business Detail Total Storage Rental Revenue $871,144 $858,656 1.5 % $769,457 13.2 % Plus: Terminations/Permanent Withdrawal Fees 9,222 8,725 5.7 % 8,614 7.1 % Total Revenue from Adjusted Storage Rental Activities $880,366 $867,381 1.5 % $778,071 13.1 % Less: Storage Rental Expenses Storage Rent 120,010 119,371 0.5 % 111,699 7.4 % Storage Rental Labor 7,489 8,777 (14.7) % 6,847 9.4 % All Other Storage Costs 138,662 127,187 9.0 % 103,933 33.4 % Storage Rental Cost of Sales $266,161 $255,335 4.2 % $222,479 19.6 % Storage Rental Gross Profit $614,205 $612,046 0.4 % $555,591 10.5 % Storage Rental Gross Margin 69.8 % 70.6 % -80 bps 71.4 % -160 bps Service Business Detail Total Service Revenue $548,685 $529,519 3.6 % $509,592 7.7 % Less: Terminations/Permanent Withdrawal Fees 9,222 8,725 5.7 % 8,614 7.1 % Total Revenue from Adjusted Service Activities $539,463 $520,794 3.6 % $500,978 7.7 % Less: Service Expenses Service Rent 6,565 7,233 (9.2) % 2,866 129.1 % Service Labor 215,310 215,846 (0.2) % 195,678 10.0 % All Other Service Costs 113,292 113,787 (0.4) % 118,959 (4.8) % Service Cost of Sales $335,167 $336,866 (0.5) % $317,502 5.6 % Service Gross Profit $204,296 $183,928 11.1 % $183,476 11.3 % Service Gross Margin 37.9 % 35.3 % 260 bps 36.6 % 130 bps Section V - Storage and Service Reconciliation investors.ironmountain.com Q4 2023 Supplemental Financial Information 21

Full Year Storage Rental and Service Business Detail Full Year 2023 Full Year 2022 % Change Storage Rental Business Detail Total Storage Rental Revenue $3,370,645 $3,034,023 11.1 % Plus: Terminations/Permanent Withdrawal Fees 33,441 34,168 (2.1) % Total Revenue from Adjusted Storage Rental Activities $3,404,086 $3,068,190 10.9 % Less: Storage Rental Expenses Storage Rent 472,994 425,401 11.2 % Storage Rental Labor 32,500 27,842 16.7 % All Other Storage Costs 504,353 438,125 15.1 % Storage Rental Cost of Sales $1,009,847 $891,367 13.3 % Storage Rental Gross Profit $2,394,239 $2,176,823 10.0 % Storage Rental Gross Margin 70.3 % 70.9 % -60 bps Service Business Detail Total Service Revenue $2,109,644 $2,069,551 1.9 % Less: Terminations/Permanent Withdrawal Fees 33,441 34,168 (2.1) % Total Revenue from Adjusted Service Activities $2,076,203 $2,035,384 2.0 % Less: Service Expenses Service Rent 24,997 16,904 47.9 % Service Labor 858,851 779,378 10.2 % All Other Service Costs 464,105 501,471 (7.5) % Service Cost of Sales $1,347,953 $1,297,753 3.9 % Service Gross Profit $728,250 $737,631 (1.3) % Service Gross Margin 35.1 % 36.2 % -110 bps Section V - Storage and Service Reconciliation investors.ironmountain.com Q4 2023 Supplemental Financial Information 22

Global Real Estate Portfolio and Lease Obligations Global Real Estate Portfolio (1) Owned Facilities Leased Facilities Total Buildings Sq. Ft. Buildings Sq. Ft. Buildings Sq. Ft. Total as of 9/30/2023 (2) 235 23,795 1,149 74,782 1,384 98,577 Additions & Expansions 1 50 13 387 14 437 Dispositions & Move Outs (4) (565) (17) (437) (21) (1,002) Total as of 12/31/2023 (3) 232 23,281 1,145 74,732 1,377 98,012 Total % 16.8 % 23.8 % 83.2 % 76.2 % Top Five Markets Owned, United States (in Sq. Ft.) Top Five Markets Owned, International (in Sq. Ft.) Northern New Jersey 1,962 Paris, France 807 Chicago 1,282 Montreal, Canada 552 Boston 1,154 Mexico City, Mexico 452 Dallas 966 Toronto, Canada 434 Houston 873 Lima, Peru 434 Facility Lease Expirations (4) (% of total square feet subject to lease) 4.3% 5.5% 5.1% 4.5% 4.9% 6.6% 5.1% 4.7% 5.0% 54.2% 2024 2025 2026 2027 2028 2029 2030 2031 2032 Thereafter Weighted-Average Remaining Operating Lease Obligation: 10.4 Years (1) Includes real estate held in consolidated joint ventures. (2) Reflects adjustments to previous periods due to refinements to real estate basis. (3) Includes 12 owned data center facilities and 5 leased data center facilities with 2.6M Sq. Ft. and 0.8M Sq. Ft., respectively. (4) Includes financing and operating lease obligations. Section VI - Real Estate Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 23

Data Center Customer Lease Expiration Year Number of Leases Expiring Total MW Expiring Percentage of Total MW Annualized GAAP TCV Rent Expiring Percentage of TCV Annualized Rent 2024 935 19.5 4.5% 65,564 10.9% 2025 346 36.4 8.4% 86,659 14.5% 2026 242 23.3 5.4% 52,198 8.7% 2027 59 9.7 2.2% 24,459 4.1% 2028 64 58.2 13.4% 74,435 12.4% 2029 15 24.6 5.7% 24,250 4.0% 2030 5 48.6 11.2% 53,808 9.0% Thereafter 23 213.5 49.2% 217,790 36.4% Total 1,689 433.8 100.0% $599,163 100.0% WALE: 8.0 years Data Center Leasing Activity Summary Q4 2023 Full Year 2023 Transaction Count GAAP MRR kW $ / kW / Month Transaction Count GAAP MRR kW $ / kW / Month New/expansion leases signed 122 $822 4,535 $181 323 $15,163 124,351 $122 New Built to Suit leases signed — — — — — — — — Commenced leases 122 2,871 30,250 95 313 6,959 70,022 99 Renewed leases 156 1,942 7,903 246 644 8,300 32,538 255 Churn 1.7% 5.7% Cash Mark to Market 4.8% 5.3% GAAP Mark to Market 9.7% 8.2% VA-7 Rendering Section VII - Data Center Customer and Portfolio Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 24

Data Center Operating Portfolio Stabilized Pre-Stabilized Total Leaseable MW Leased % by MW Leaseable MW Leased % by MW Leaseable MW Leased % by MW Boyers and Other WPA-1 and Other 14.2 79.6% — — 14.2 79.6% Phoenix AZP-1 41.0 100.0% — — 41.0 100.0% AZP-2 40.5 100.0% — — 40.5 100.0% Scottsdale AZS-1 5.7 100.0% — — 5.7 100.0% Denver DEN-1 11.3 47.0% — — 11.3 47.0% New Jersey NJE-1 16.8 98.2% 4.0 62.5% 20.8 91.3% Northern Virginia VA-1 12.4 100.0% — — 12.4 100.0% VA-2 30.0 100.0% 6.0 79.2% 36.0 96.5% VA-3 10.0 100.0% — — 10.0 100.0% Amsterdam AMS-1 13.1 92.2% — — 13.1 92.2% London LON-1 8.7 97.5% — — 8.7 97.5% LON-2 9.0 100.0% — — 9.0 100.0% Frankfurt FRA-1 9.0 100.0% — — 9.0 100.0% FRA-2 9.8 100.0% — — 9.8 100.0% Singapore SIN-1 6.8 100.0% — — 6.8 100.0% Madrid MAD-1 1.0 45.0% — — 1.0 45.0% India Web Werks JV 1.5 100.0% 4.7 30.2% 6.2 47.3% Total Data Center Properties 240.8 95.4% 14.7 59.1% 255.4 93.3% Total Potential Capacity - Megawatts Q4 2023 Q4 2022 Leasable 255.4 191.6 Under Construction 229.7 172.9 Held for Development 375.7 382.6 Total Data Center Portfolio 860.8 747.1 Section VII - Data Center Customer and Portfolio Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 25

Data Center Expansion and Development Activity Project / Facilities MW Under Construction MW Pre- leased % Pre- Leased Investment in Q4 2023 ($M) Cumulative Investment ($M) Total Expected Investment ($M) Expected Completion Expected Stabilization MW Held for Development Data Center Expansion Amsterdam AMS-1 Phase 4 5.0 — — $10.1 $31.5 $45.0 Q3 2025 Q3 2026 4.6 Phoenix AZP-2 Phase 8 6.0 6.0 100.0% $5.7 $28.1 $39.2 Q1 2024 Q1 2024 1.5 Madrid MAD-1 Phase 1 2.0 — — $3.6 $8.0 $30.1 Q3 2024 Q3 2025 — India Web Werks JV (1) 6.7 1.8 26.9% — — — 6.8 All Other Facilities — 1.0 — — — — 19.9 Total Expansion 19.7 8.8 44.7% $19.4 $67.6 $114.3 32.8 New Development Phoenix AZP-3 — — — — — — 36.0 Amsterdam AMS-2 — — — — — — 10.6 Chicago CHI-2 — — — — — — 36.0 Frankfurt FRA-1 Phase 2 (2) 9.0 9.0 100.0% — — — Q1 2024 Q4 2024 — FRA-1 Phase 3 9.0 9.0 100.0% — — — Q1 2024 Q2 2027 — London LON-2 Phase 2 9.0 9.0 100.0% $5.6 $56.7 $61.0 Q1 2024 Q4 2025 — LON-2 Phase 3 9.0 9.0 100.0% $6.7 $32.7 $62.8 Q4 2024 Q4 2028 — LON-3 Future Phases — — — — — — 25.0 Madrid MAD-1 — — — — — — 76.0 Northern Virginia VA-3 Phase 2 34.0 34.0 100.0% $37.1 $78.1 $204.1 Q4 2024 Q4 2024 — VA-4 (3) 32.0 32.0 100.0% $13.4 $28.2 $96.2 Q3 2025 Q3 2025 — VA-5 (3) 40.0 40.0 100.0% $18.7 $40.6 $109.5 Q2 2025 Q2 2025 — VA-6 Phase 1 16.0 16.0 100.0% $41.5 $64.9 $178.5 Q4 2024 Q4 2024 — VA-6 Phase 2 16.0 8.0 50.0% $10.0 $10.0 $111.5 Q1 2025 Q1 2026 — VA-7 36.0 36.0 100.0% $3.4 $9.3 $360.0 Q4 2025 Q4 2025 — VA Future Phases — — — — — — 44.0 India Web Werks JV (1) — — — — — — 99.3 Miami MIA-1 — — — — — — 16.0 Total New Development 210.0 202.0 96.2% $136.3 $320.5 $1,183.6 342.9 Total Development 229.7 210.8 91.8% $155.7 $388.1 $1,297.9 375.7 (1) Represents a consolidated joint venture in India; operating six facilities in six markets. (2) FRA-1 is an unconsolidated joint venture; construction costs are funded by the Joint Venture with Iron Mountain managing the construction. (3) VA-4/5 are held by a consolidated joint venture; construction costs are funded by the Joint Venture with Iron Mountain managing the construction. Section VII - Data Center Customer and Portfolio Metrics investors.ironmountain.com Q4 2023 Supplemental Financial Information 26

Capitalization Senior Secured Credit Facility Total Market Capitalization as of 12/31/2023 Capacity $2,478,125 # of Shares Outstanding 292,143 Outstanding $228,125 Share Price as of 12/31/23 $69.98 Letters of Credit $4,821 Total Market Capitalization $20,444,149 Remaining Capacity $2,245,179 Net Debt (1) $11,811,833 Interest Rate Spread (Prime) 0.75 % Total Enterprise Value $32,255,981 Interest Rate Spread (SOFR+CSA) 1.85 % Net Debt to Total Enterprise Value 36.6 % Weighted Average Interest Rate 7.10 % Adjusted EBITDA to Interest Expense 3.5x Maturity Date 3/18/2027 Total Enterprise Value to Adjusted EBITDA (2) 16.4x Credit Facility Fixed Charge Coverage Ratio 2.4x Net Total Lease-Adjusted Leverage Ratio 5.1x Fixed vs. Floating Rate Debt 80% 20% Fixed Rate Debt Floating Rate Debt Credit Rating S&P Moody's Corporate BB- Ba3 Senior Credit Facility BB Ba3 Outlook Stable Stable Latest Update 12/15/2023 12/20/2023 Total Long Term Debt Weighted Average Rates Weighted Average Interest 5.7 % Weighted Average Maturity 6.1 Years USD denominated 87 % Debt Maturity Profile ($ in Millions) (3) (4) $48 $1,102 $1,010 $1,203 $1,346 $2,034 $1,312 $2,216 $1,350 Senior Secured Credit Facility Bi-Lateral Loans Construction Loans IMDC AUD Term Loan B A/R Securitization USD Term Loan B (2026) USD Term Loan B (2031) Mortgage Notes Payable Senior Unsecured Notes 2024 2025 2026 2027 2028 2029 2030 2031 2032 (1) Net debt is calculated as current portion of long-term debt of $120.7M plus long-term debt net of current portion of $11,812.5M plus deferred financing costs of $101.5M less cash and cash equivalents of $222.8M. (2) Total Enterprise Value to Adjusted EBITDA is calculated on a trailing twelve-month basis. (3) Excludes Deferred Financing Costs, Discounts, Financing Leases, Notes Payable and Other. (4) In addition to the above, the company has approximately $363M of committed asset level financing for the construction of three Data Center assets in Northern Virginia. Section VIII - Capitalization and Debt Maturity Profile investors.ironmountain.com Q4 2023 Supplemental Financial Information 27

Quarterly Capital Expenditures Q4 2023 Q3 2023 Q/Q % Change Q4 2022 Y/Y % Change Growth: Data Center $310,230 $236,107 31.4 % $196,860 57.6 % Real Estate 64,862 31,312 107.1 % 66,911 (3.1) % Innovation and Other 23,803 19,688 20.9 % 14,563 63.4 % Total Growth Capital Expenditures $398,895 $287,107 38.9 % $278,335 43.3 % Recurring: Data Center $5,249 $5,534 (5.1) % $7,588 (30.8) % Real Estate 23,886 15,027 59.0 % 16,060 48.7 % Non-Real Estate 15,781 14,300 10.4 % 12,692 24.3 % Total Recurring Capital Expenditures $44,916 $34,861 28.8 % $36,340 23.6 % Total Growth and Recurring Capital Expenditures $443,811 $321,968 37.8 % $314,675 41.0 % Net Change in Prepaid and Accrued Capital Expenditures (66,882) 39,568 n/a (36,098) 85.3 % Total Cash Paid for Growth and Recurring Capital Expenditures $376,929 $361,536 4.3 % $278,577 35.3 % Full Year Capital Expenditures Full Year 2023 Full Year 2022 % Change Growth: Data Center $964,198 $592,875 62.6 % Real Estate 201,036 181,285 10.9 % Innovation and Other 81,135 45,371 78.8 % Total Growth Capital Expenditures $1,246,369 $819,531 52.1 % Recurring: Data Center $17,198 $17,008 1.1 % Real Estate 58,465 60,354 (3.1) % Non-Real Estate 64,743 65,134 (0.6) % Total Recurring Capital Expenditures $140,406 $142,496 (1.5) % Total Growth and Recurring Capital Expenditures $1,386,775 $962,027 44.2 % Net Change in Prepaid and Accrued Capital Expenditures (47,552) (86,649) (45.1) % Total Cash Paid for Growth and Recurring Capital Expenditures $1,339,223 $875,378 53.0 % TTM Recurring Capex as a % of Revenue (excl. Data Center) 2.7% 2.6% 2.3% 2.3% 2.5% Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 TTM Data Center Recurring CapEx as a % of Data Center Revenue 4.2% 4.0% 4.1% 4.2% 3.5% Q4 2022 Q1 2023 Q2 2023 Q3 2023 Q4 2023 Section IX - Capital Expenditures investors.ironmountain.com Q4 2023 Supplemental Financial Information 28

Non-GAAP Measures and Definitions Non-GAAP measures are supplemental metrics designed to enhance our disclosures and to provide additional information that we believe to be important for investors to consider when evaluating our financial performance. These non-GAAP measures should be considered in addition to, but not as a substitute for, other measures of financial performance reported in accordance with accounting principles generally accepted in the United States of America (“GAAP”), such as operating income, income (loss) from continuing operations, net income (loss) or cash flows from operating activities from continuing operations (as determined in accordance with GAAP). SRP FLS Statement: We have made statements in this Supplemental Financial Information that constitute "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995 and other securities laws. These forward-looking statements concern our current expectations regarding our future results from operations, economic performance, financial condition, goals, strategies, investment objectives, plans and achievements. These forward-looking statements are subject to various known and unknown risks, uncertainties and other factors, and you should not rely upon them except as statements of our present intentions and of our present expectations, which may or may not occur. When we use words such as “believes”, “expects”, “anticipates”, “estimates”, “plans”, “intends”, “pursue”, “will” or similar expressions, we are making forward-looking statements. Although we believe that our forward-looking statements are based on reasonable assumptions, our expected results may not be achieved, and actual results may differ materially from our expectations. In addition, important factors that could cause actual results to differ from expectations include, among others: (i) our ability or inability to execute our strategic growth plan, including our ability to invest according to plan, grow our businesses (including through joint ventures), incorporate alternative technologies into our offerings, achieve satisfactory returns on new product offerings, continue our revenue management, expand and manage our global operations, complete acquisitions on satisfactory terms, integrate acquired companies efficiently and transition to more sustainable sources of energy; (ii) changes in customer preferences and demand for our storage and information management services, including as a result of the shift from paper and tape storage to alternative technologies that require less physical space; (iii) the impact of our distribution requirements on our ability to execute our business plan; (iv) the costs of complying with and our ability to comply with laws, regulations and customer requirements, including those relating to data privacy and cybersecurity issues, as well as fire and safety and environmental standards; (v) the impact of attacks on our internal information technology (“IT”) systems, including the impact of such incidents on our reputation and ability to compete and any litigation or disputes that may arise in connection with such incidents; (vi) our ability to fund capital expenditures; (vii) our ability to remain qualified for taxation as a real estate investment trust for United States federal income tax purposes (“REIT”); (viii) changes in the political and economic environments in the countries in which we operate and changes in the global political climate; (ix) our ability to raise debt or equity capital and changes in the cost of our debt; (x) our ability to comply with our existing debt obligations and restrictions in our debt instruments; (xi) the impact of service interruptions or equipment damage and the cost of power on our data center operations; (xii) the cost or potential liabilities associated with real estate necessary for our business; (xiii) unexpected events, including those resulting from climate change or geopolitical events, could disrupt our operations and adversely affect our reputation and results of operations; (xiv) failures to implement and manage new IT systems; (xv) other trends in competitive or economic conditions affecting our financial condition or results of operations not presently contemplated; and (xvi) the other risks described in our periodic reports filed with the SEC, including under the caption “Risk Factors” in Part I, Item 1A of our Annual Report. Except as required by law, we undertake no obligation to update any forward-looking statements appearing in this Supplemental Financial Information. Acquisition and Integration Costs: We define Acquisition and Integration Costs as operating expenditures directly associated with the closing and integration activities of our business acquisitions that have closed, or are highly probable of closing, and include (i) advisory, legal and professional fees to complete business acquisitions and (ii) costs to integrate acquired businesses into our existing operations, including move, severance, and system integration costs. Adjusted Earnings Per Share, or Adjusted EPS: We define Adjusted EPS as reported earnings per share fully diluted from net income (loss) attributable to Iron Mountain Incorporated (inclusive of our share of adjusted losses (gains) from our unconsolidated joint ventures) and excluding certain items, specifically: (i) Acquisition and Integration Costs; (ii) Restructuring and other transformation; (iii) Amortization related to the write-off of certain customer relationship intangible assets; (iv) (Gain) loss on disposal/write-down of property, plant and equipment, net (including real estate); (v) Other expense (income), net; (vi) Stock-based compensation expense; (vii) Non-cash amortization related to derivative instruments; and (viii) Tax impact of reconciling items and discrete tax items. We do not believe these excluded items to be indicative of our ongoing operating results, and they are not considered when we are forecasting our future results. We believe Adjusted EPS is of value to our current and potential investors when comparing our results from past, present and future periods. Non-Cash Amortization of Derivative Instruments: Includes amortization on instruments such as cross-currency swap agreements designated as a hedge of net investment. Adjusted EBITDA and Adjusted EBITDA Margin: We define Adjusted EBITDA as net income (loss) before interest expense, net, provision (benefit) for income taxes, depreciation and amortization (inclusive of our share of Adjusted EBITDA from our unconsolidated joint ventures), and excluding certain items we do not believe to be indicative of our core operating results, specifically: (i) Acquisition and Integration Costs; (ii) Restructuring and other transformation; (iii) (Gain) loss on disposal/write-down of property, plant and equipment, net (including real estate); (iv) Other expense (income), net; and (v) Stock-based compensation expense. Adjusted EBITDA Margin is calculated by dividing Adjusted EBITDA by total revenues. We use multiples of current or projected Adjusted EBITDA in conjunction with our discounted cash flow models to determine our estimated overall enterprise valuation and to evaluate acquisition targets. We believe Adjusted EBITDA and Adjusted EBITDA Margin provide our current and potential investors with relevant and useful information regarding our ability to generate cash flows to support business investment. These measures are an integral part of the internal reporting system we use to assess and evaluate the operating performance of our business. Adjusted Funds From Operations, or AFFO: We define adjusted funds from operations or AFFO as FFO (Normalized) (1) excluding (i) non-cash rent expense (income); (ii) depreciation on non-real estate assets; (iii) amortization expense associated with customer and supplier relationship value, intake costs, acquisitions of customer relationships and other intangibles; (iv) amortization of deferred financing costs and debt discount/premium; (v) revenue reduction associated with amortization of customer inducements and above- and below-market data center leases; and (vi) the impact of reconciling to normalized cash taxes; and (2) including recurring capital expenditures. We also adjust for these items to the extent attributable to our portion of Section X - Appendix and Definitions investors.ironmountain.com Q4 2023 Supplemental Financial Information 29

unconsolidated ventures. We believe that AFFO, as a widely recognized measure of operations of REITs, is helpful to investors as a meaningful supplemental comparative performance measure to other REITs, including on a per share basis. AFFO should be considered in addition to, but not as a substitute for, other measures of financial performance reported in accordance with GAAP, such as operating income, net income (loss) or cash flows from operating activities (as determined in accordance with GAAP). Effective Q4 2023, our AFFO definition has been updated to exclude amortization of capitalized commissions. With this change, our calculation more accurately represents our funds available to support growth, and is more comparable to our peers, including those in the data center industry. AFFO per share: Calculated as AFFO divided by weighted-average fully-diluted shares outstanding. Funds From Operations, FFO (Nareit), and FFO (Normalized): Funds from operations ("FFO") is defined by the National Association of Real Estate Investment Trusts as net income (loss) excluding depreciation on real estate assets, losses and gains on sale of real estate, net of tax, and amortization of data center leased-based intangibles (“FFO (Nareit)”). We calculate our FFO measures, including FFO (Nareit), adjusting for our share of reconciling items from our unconsolidated joint ventures. FFO (Nareit) does not give effect to real estate depreciation because these amounts are computed, under GAAP, to allocate the cost of a property over its useful life. Because values for well-maintained real estate assets have historically increased or decreased based upon prevailing market conditions, we believe that FFO (Nareit) provides investors with a clearer view of our operating performance. Our most directly comparable GAAP measure to FFO (Nareit) is net income (loss). We modify FFO (Nareit), as is common among REITs seeking to provide financial measures that most meaningfully reflect their particular business ("FFO (Normalized)"). Our definition of FFO (Normalized) excludes certain items included in FFO (Nareit) that we believe are not indicative of our core operating results, specifically: (i) Acquisition and Integration Costs; (ii) Restructuring and other transformation; (iii) (Gain) loss on disposal/write-down of property, plant and equipment, net (excluding real estate); (iv) Other expense (income), net; (v) Stock-based compensation expense; (vi) Non-cash amortization related to derivative instruments; (vii) Real estate financing lease depreciation; and (viii) Tax impact of reconciling items and discrete tax items. FFO (Normalized) per share: FFO (Normalized) divided by weighted-average fully-diluted shares outstanding. Terminations/Permanent Withdrawal Fees: Revenue from the preparation, documentation, and permanent withdrawal of records. Business Segments: The Global Records and Information Management ("Global RIM") Business segment includes several distinct offerings: Records Management, stores physical records and provides information services, vital records services, courier operations, and the collection, handling and disposal of sensitive documents ("Records Management") for customers in 60 countries around the globe. As of December 31, 2023, we stored approximately 731.5 million cubic feet of hardcopy records. Data Management, provides storage and rotation of backup computer media as part of corporate disaster recovery plans, including service and courier operations, server and computer backup services and related services offerings ("Data Management"). Global Digital Solutions, develops, implements and supports comprehensive storage and information management solutions for the complete lifecycle of our customers’ information, including the management of physical records, conversion of documents to digital formats and digital storage of information ("Global Digital Solutions"). Secure Shredding, includes the scheduled pick-up of office records that customers accumulate in specially designed secure containers we provide and is a natural extension of our hardcopy records management operations, completing the lifecycle of a record. Through a combination of shredding facilities and mobile shredding units consisting of custom built trucks, we are able to offer secure shredding services to our customers. Entertainment Services, entertainment and media services which help industry clients store, safeguard and deliver physical media of all types, and provides digital content repository systems that house, distribute, and archive key media assets ("Entertainment Services"). Consumer Storage, provides on-demand, valet storage for consumers ("Consumer Storage") utilizing data analytics and machine learning to provide effective customer acquisition and a convenient and seamless consumer storage experience. Global Data Center Business: Provides enterprise-class data center facilities and hyperscale-ready capacity to protect mission-critical assets and ensure the continued operation of our customers’ IT infrastructure, with secure, reliable and flexible data center options. Corporate and Other: Consists primarily of our Fine Arts and asset lifecycle management ("ALM") businesses and other corporate items. Our Fine Arts business provides technical expertise in the handling, installation and storing of art. Our ALM business provides hyperscale and corporate IT infrastructure managers with services and solutions that enable the decommissioning, data erasure processing and disposition or sale of IT hardware and component assets. ALM services are enabled by: secure logistics, chain of custody and complete asset traceability practices, environmentally-responsible asset processing and recycling, and data sanitization and asset refurbishment services that enable value recovery through asset remarketing. In addition, ALM also offers workplace IT asset management services including storage, configuration, deployment, device support and end-of-life disposition for employee IT devices. Our ALM service focus on protecting and eradicating customer data while maintaining strong, auditable, and transparent chain of custody practices. Corporate and Other also includes costs related to executive and staff functions, including finance, human resources and IT, which benefit the enterprise as a whole. Capital Expenditures and Investments: Our business requires capital expenditures to support our expected storage rental revenue and service revenue growth and ongoing operations, new products and services and increased profitability. The majority of our capital goes to support business line growth and our ongoing operations. Additionally, we invest capital to acquire or construct real estate. We also expend capital to support the development and Section X - Appendix and Definitions investors.ironmountain.com Q4 2023 Supplemental Financial Information 30

improvement of products and services and projects designed to increase our profitability. These expenditures are generally discretionary in nature. We categorize our capital expenditures as follows: Growth Investment: Data Center - Expenditures primarily related to investments in the construction of data center facilities (including the acquisition of land), as well as investments to drive revenue growth, expand capacity or achieve operational or cost efficiencies. Real Estate - Expenditures primarily related to investments in land, buildings, building improvements, leasehold improvements and racking structures to grow our revenues, extend the useful life of an asset or achieve operational or cost efficiencies. Innovation and Other - Discretionary capital expenditures for significant new products and services as well as computer hardware and software to support new products and services or to achieve operational or cost efficiencies. Integration costs of acquisitions are also included. Recurring: Data Center - Expenditures related to the replacement of equivalent components and overall maintenance of existing data center assets. Real Estate - Expenditures primarily related to the replacement of components of real estate assets such as buildings, building improvements, leasehold improvements and racking structures. Non-Real Estate - Expenditures primarily related to the replacement of containers and shred bins, warehouse equipment, fixtures, computer hardware, or third-party or internally-developed software assets that support the maintenance of existing revenues or avoidance of an increase in costs. Constant Currency: Adjusts results to normalize Fx impacts across comparable periods. Data Center Business Definitions: Leaseable MW - Represents the amount of critical power capacity available for customer use, measured in megawatts (MW). Leased % Calculation - Calculated as the megawatts under contract divided by the leasable megawatts. Monthly Recurring Revenue (MRR) - Defined as recurring contractual revenue under existing commenced customer leases, including rent, power, and other recurring data center services. Pre-leased - A lease on data center capacity that is signed before construction has completed. Pre-Stabilized - A building recently placed in service which has not yet reached 85% leased or 24 months in service. Rental Churn Rate - Represents data center leases which are not renewed or are terminated during the period. Rental churn is calculated based on the MRR terminated in the period, compared with total MRR at the beginning of the period. TCV - “Total Contract Value” represents total revenue contracted for active contracts through the contract term, not including renewals or extensions, but including fixed power charges. Total potential MW - Total amount of existing and planned critical power capacity at full build-out, measured in megawatts. WALE - “Weighted Average Lease Expiry” (in years) is calculated on a revenue basis, using annual GAAP revenue of all in-place contracts, excluding utility reimbursements. EBITDAR: Calculated as the last 12 months' earnings before interest, taxes, depreciation and amortization and rent expense (“EBITDAR”) of our consolidated subsidiaries, other than those we have designated as “Unrestricted Subsidiaries” as defined in our Credit Agreement, subject to certain adjustments and exclusions, which make the calculation of financial performance for purposes of EBITDAR calculations not directly comparable to our presentation of Adjusted EBITDA. Credit Facility Fixed Charge Coverage Ratio: Calculated as last twelve months EBITDAR divided by scheduled amortization, interest expense related to outstanding debt and preferred equity, if any, and rent expenses. Net Lease-Adjusted Leverage Ratio: Calculated as net debt, including the capitalized value of lease obligations, plus six times rent expenses divided by EBITDAR. Organic Revenue Growth: Our organic revenue growth rate, represents the year-over-year growth rate of our revenues excluding the impact of business acquisitions, divestitures and foreign currency exchange rate fluctuations. Our organic revenue growth rates includes the impact of acquisitions of customer relationships. Records Management Retention Rate: Calculated as one minus the result of dividing the total number of cubic feet of records removed from inventory due to customer terminations and destructions in a one-year period by the total number of cubic feet of records in storage at the beginning of the period. Storage Rev/NOI per Sq. Ft.: Calculated as either storage revenue or Storage NOI (as defined below) divided by the quarterly building square foot average for storage products. Service Profit and Margin: The Gross Profit and Margin attributable to the global service business. Calculated as follows: Total Revenues from Adjusted Service Activities - Service Cost of Sales = Service Gross Profit ($) / Total Revenues from Adjusted Service Activities = Service Gross Margin (%) Section X - Appendix and Definitions investors.ironmountain.com Q4 2023 Supplemental Financial Information 31

Storage Net Operating Income, or Storage NOI: Storage NOI is defined as revenue from rental activities (storage rental revenue, termination fees and permanent withdrawal fees) less storage rental costs. Storage rental costs include facility costs (excluding rent), storage rental labor, other storage costs and allocated overhead. Storage NOI is commonly used in the REIT industry and enables investors to understand and value the income generated from the company’s real estate. Storage Profit and Margin: Gross Profit and Margin attributable to the global storage business. Calculated as follows: Total Revenue from Adjusted Storage Rental Activities - Storage Rental Cost of Sales = Storage Rental Gross Profit ($) / Total Revenue from Adjusted Storage Rental Activities = Storage Rental Gross Margin (%) Tax Rates: Effective Tax Rate - GAAP tax rate for the period calculated as tax expense or benefit for the quarter (total of current and deferred tax provisions), including discrete items, and divided by profit before tax for the period. Structural Tax Rate - Estimated tax rate for the full fiscal year calculated based on forecasted ordinary income and forecasted tax expense/benefit excluding any significant unusual or infrequently occurring items (i.e., discrete items) and items recognized net of tax on the financials (i.e., discontinued operations). Total Storage Volume: Iron Mountain’s comprehensive portfolio of physical storage, including Global RIM and Corporate and Other, calculated on an absolute basis in cubic feet. Section X - Appendix and Definitions investors.ironmountain.com Q4 2023 Supplemental Financial Information 32