Supplemental Financial Information Third Quarter 2022 investors.ironmountain.com

Table of Contents Section I - Q3 Earnings Press Release 3 Q3 2022 Earnings Press Release 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 Year to Date Operating Performance 10 Section IV - Balance Sheets, Statements of Operations and Reconciliations Condensed Consolidated Balance Sheets 11 Quarterly Condensed Consolidated Statements of Operations 12 Year to Date Condensed Consolidated Statements of Operations 13 Quarterly and Year to Date Reconciliation of Net Income (Loss) to Adjusted EBITDA 14 Quarterly and Year to Date Reconciliation of Reported Earnings per Share to Adjusted Earnings per Share 15 Quarterly Reconciliation of Net Income (Loss) to FFO and AFFO 16 Year to Date Reconciliation of Net Income (Loss) to FFO and AFFO 18 Section V - Storage and Service Reconciliation Quarterly Storage Rental and Service Business Detail 20 Year to Date Storage and Service Business Detail 21 Section VI - Real Estate Metrics 22 Global Real Estate Portfolio and Lease Obligations Facility Lease Expirations Section VII - Data Center Customer and Portfolio Metrics Data Center Customer Lease Expiration and Leasing Activity Summary 23 Data Center Operating Portfolio and Total Potential Capacity 24 Data Center Expansion and Development Activity 25 Section VIII - Capitalization and Debt Maturity Profile 26 Capitalization Total Borrowings Maturity Schedule Debt Maturity Profile Section IX - Capital Expenditures 27 Quarterly and Year to Date Capital Expenditures and Investments Section X - Appendix and Definitions 28 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 September 30, 2022 unless noted Unaudited investors.ironmountain.com Q3 2022 Supplemental Financial Information 2

Iron Mountain Reports Third Quarter Results -- Net Income of $193 million; achieves record quarterly Adjusted EBITDA and AFFO -- BOSTON – November 3, 2022 – Iron Mountain Incorporated (NYSE: IRM), a global leader in innovative storage, data center infrastructure, asset lifecycle management and information management services, announces record financial and operating results for the third quarter of 2022. The conference call / webcast details, earnings call presentation and supplemental financial information, which includes definitions of certain capitalized terms used in this release, are available on Iron Mountain’s Investor Relations website. Reconciliations of non-GAAP measures to the appropriate GAAP measures are included herein. “We are pleased to report a set of very strong results for the third quarter, including all-time record Adjusted EBITDA and AFFO. As we shared with the market at our Investor Event in September, we have set out a path for our growth trajectory with Project Matterhorn,” said William L. Meaney, President and CEO of Iron Mountain. “In doing so, our expanded total addressable market along with our widened suite of solutions have enabled us to continue our mission of delivering value for our customers and as a result to achieve revenue growth of 18% and growth in Adjusted EBITDA of 16% on a constant currency basis, or 14% and 12%, respectively, on a reported basis.” Financial Performance Highlights for the Third Quarter and Year-to-Date 2022 ($ in millions, except per share data) Three Months Ended Y/Y % Change Year to Date Y/Y % Change 9/30/22 9/30/21 Reported $ Constant Fx 9/30/22 9/30/21 Reported $ Constant Fx Storage Rental Revenue $760 $719 6% 10% $2,265 $2,145 6% 9% Service Revenue $527 $412 28% 33% $1,560 $1,187 31% 35% Total Revenue $1,287 $1,130 14% 18% $3,825 $3,332 15% 18% Net Income $193 $68 n/a $436 $391 12% Reported EPS $0.66 $0.23 n/a $1.49 $1.34 11% Adjusted EPS $0.48 $0.40 20% $1.34 $1.09 23% Adjusted EBITDA $469 $418 12% 16% $1,355 $1,204 13% 16% Adjusted EBITDA Margin 36.5% 37.0% (50) bps 35.4% 36.1% (70) bps AFFO $288 $263 9% $823 $745 11% AFFO per share $0.98 $0.90 9% $2.82 $2.56 10% • Total reported Revenues for the third quarter were $1.29 billion, compared with $1.13 billion in the third quarter of 2021, an increase of 13.9%. Excluding the impact of foreign currency exchange (Fx), total reported Revenues increased 18.2% compared to the prior year, driven by a 32.8% increase in Service revenue, while Storage rental revenue increased 9.8%. Total service revenue growth was driven by the inclusion of ITRenew; on an organic constant currency basis, service revenue grew 21.8%. Year to date, total reported Revenues increased 14.8%, or 18.0% excluding the impact of Fx. • Net Income for the third quarter was $192.9 million compared with $68.1 million in the third quarter of 2021. Year to date, Net Income was $436.5 million, compared with $391.3 million in 2021. • Adjusted EBITDA for the third quarter was $469.4 million, compared with $417.8 million in the third quarter of 2021, an increase of 12.4%. On a constant currency basis, Adjusted EBITDA increased by 16.5% in the third quarter, driven by the strong increase in Service revenue and productivity benefits. Year to date, Adjusted EBITDA was $1.4 billion, compared with $1.2 billion in 2021, an increase of 12.6%. On a constant currency basis, year to date Adjusted EBITDA increased 15.8%. • FFO (Normalized) per share was $0.76 for the third quarter, compared with $0.72 in the third quarter of 2021, an increase of 5.6%. Year to date, FFO (Normalized) per share was $2.17, compared with $2.03 in 2021, or an increase of 7.2%. • AFFO was $288.0 million for the third quarter, compared with $263.5 million in the third quarter of 2021, an increase of 9.3%, driven by improved Adjusted EBITDA, partially offset by increases in interest expense and cash taxes. Year to date, AFFO was $823.1 million, compared with $744.9 million in 2021, or an increase of 10.5%. Section I - Q3 Earnings Press Release investors.ironmountain.com Q3 2022 Supplemental Financial Information 3

• AFFO per share was $0.98 for the third quarter, compared with $0.90 in the third quarter of 2021, an increase of 8.9%, driven by improved Adjusted EBITDA, partially offset by increases in interest expense and cash taxes. Year to date, AFFO per share was $2.82, compared with $2.56 in 2021, or an increase of 9.9%. Dividend On November 3, 2022, Iron Mountain's Board of Directors declared a quarterly cash dividend of $0.6185 per share for the fourth quarter. The fourth quarter 2022 dividend is payable on January 5, 2023, for shareholders of record on December 15, 2022. Guidance Iron Mountain affirmed full year 2022 guidance; details are summarized in the table below. 2022 Guidance(1) ($ in millions, except per share data) 2022 Guidance Y/Y % Change Total Revenue $5,125 - $5,275 14% - 17% Adjusted EBITDA $1,800 - $1,850 10% - 13% AFFO $1,085 - $1,120 7% - 11% AFFO Per Share $3.70 - $3.82 6% - 10% (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. About Iron Mountain Iron Mountain Incorporated (NYSE: IRM) is a global leader in innovative storage, data center infrastructure, asset lifecycle management and information management services. Founded in 1951 and trusted by more than 225,000 customers worldwide, Iron Mountain helps customers CLIMB HIGHER™ to transform their businesses. Through a range of services 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 Twitter and LinkedIn. Section I - Q3 Earnings Press Release investors.ironmountain.com Q3 2022 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 internationally and manage our international 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 severity and duration of the COVID-19 pandemic and its effects on the global economy, including its effects on us, the markets we serve and our customers and the third parties with whom we do business within those markets; (v) our ability to fund capital expenditures; (vi) our ability to remain qualified for taxation as a real estate investment trust for United States federal income tax purposes; (vii) 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; (viii) 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; (ix) changes in the political and economic environments in the countries in which our international subsidiaries operate and changes in the global political climate, particularly as we consolidate operations and move records and data across borders; (x) our ability to raise debt or equity capital and changes in the cost of our debt; (xi) our ability to comply with our existing debt obligations and restrictions in our debt instruments; (xii) the impact of service interruptions or equipment damage and the cost of power on our data center operations; (xiii) the cost or potential liabilities associated with real estate necessary for our business; (xiv) failures to implement and manage new IT systems; (xv) unexpected events, including those resulting from climate change or geopolitical events, which could disrupt our operations and adversely affect our reputation and results of operations; (xvi) other trends in competitive or economic conditions affecting our financial condition or results of operations not presently contemplated; and (xvii) 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 Sarah Barry SVP, Head of Investor Relations Senior Manager, Investor Relations Gillian.Tiltman@ironmountain.com Sarah.Barry@ironmountain.com (617) 286-4881 (617) 237-6597 Section I - Q3 Earnings Press Release investors.ironmountain.com Q3 2022 Supplemental Financial Information 5

Facts and Figures $5.0 Billion Trailing Twelve-Month Revenue 225,000+ Customer Accounts ~25,000 Employees ~1,400 Facilities Worldwide 89 million+ Pieces of Media 730+ million Cubic Feet of Global Storage Volume Financial Highlights Q3 2022 Q2 2022 Q1 2022 Q4 2021 Q3 2021 Storage Rental Revenue $760,370 $753,126 $751,070 $725,177 $718,614 Service Revenue $526,575 $536,408 $496,976 $434,410 $411,534 Total Revenues $1,286,945 $1,289,534 $1,248,046 $1,159,587 $1,130,148 Adjusted EBITDA $469,434 $454,706 $430,994 $430,734 $417,769 Adjusted EBITDA Margin 36.5 % 35.3 % 34.5 % 37.1 % 37.0 % Net Income (Loss) Attributable to Iron Mountain Incorporated $192,164 $200,081 $42,299 $61,648 $67,683 Reported EPS - Fully Diluted $0.66 $0.68 $0.14 $0.21 $0.23 Adjusted EPS $0.48 $0.46 $0.38 $0.43 $0.40 FFO (Normalized) $223,315 $216,240 $193,103 $216,757 $208,836 FFO (Normalized) per Share $0.76 $0.74 $0.66 $0.74 $0.72 AFFO $287,971 $270,934 $264,234 $267,032 $263,484 AFFO per Share $0.98 $0.93 $0.91 $0.92 $0.90 Dividend per Share $0.62 $0.62 $0.62 $0.62 $0.62 TTM AFFO Payout Ratio 66.3 % 67.8 % 69.3 % 71.2 % 76.8 % Weighted Average Common Shares Outstanding - Diluted 292,552 292,487 291,846 291,811 291,482 Net Lease-Adjusted Leverage Ratio 5.2x 5.3x 5.4x 5.3x 5.4x Operating Highlights Q3 2022 Q2 2022 Q1 2022 Q4 2021 Q3 2021 Organic Storage Rental Revenue Growth 9.7 % 8.2 % 6.8 % 3.6 % 2.3 % Organic Service Revenue Growth 21.8 % 21.1 % 16.1 % 17.6 % 17.7 % Total Storage Volume 732,211 730,001 727,653 726,246 726,831 Storage Facility Capacity Utilization 79.8 % 81.3 % 80.9 % 80.9 % 81.8 % Records Management Retention Rate 93.4 % 93.8 % 93.8 % 94.1 % 94.4 % Storage Revenue / Sq. Ft. $8.35 $8.27 $8.21 $7.86 $7.83 Storage NOI / Sq. Ft. $6.70 $6.64 $6.60 $6.45 $6.39 Data Center: Leasable Megawatts 190.6 179.8 176.8 176.4 156.6 Leased % - Stabilized 93.0 % 91.8 % 91.6 % 91.2 % 89.4 % Leased % - Total 92.0 % 90.6 % 90.7 % 89.3 % 85.0 % Kilowatts Leased - New/Expansion 6,901 83,046 35,048 27,199 8,989 Churn 0.6 % 0.6 % 2.0 % 0.8 % 3.9 % Number of Facilities 20 20 20 19 19 Number of Markets 18 18 18 16 16 Section II - Financial Highlights and Organic Growth investors.ironmountain.com Q3 2022 Supplemental Financial Information 6

Organic Revenue Growth (1) Q3 2022 Q2 2022 YTD 2022 Reported Constant Currency Organic Revenue Reported Constant Currency Organic Revenue Reported Constant Currency Organic Revenue Storage Rental 5.8% 9.8% 9.7% 4.9% 7.8% 8.2% 5.6% 8.5% 8.2% Service 28.0% 32.8% 21.8% 33.6% 37.6% 21.1% 31.4% 35.3% 19.7% Total Revenues 13.9% 18.2% 14.1% 15.2% 18.5% 12.8% 14.8% 18.0% 12.4% Total Organic Revenue Growth (3.4)% (0.6)% 9.7% 7.4% 8.5% 10.0% 12.8% 14.1% Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 (8.0)% (4.0)% 0.0% 4.0% 8.0% 12.0% 16.0% Organic Storage Rental Revenue Growth 1.7% 1.7% 2.5% 2.3% 3.6% 6.8% 8.2% 9.7% Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% Organic Service Revenue Growth (12.1)% (4.8)% 25.5% 17.7% 17.6% 16.1% 21.1% 21.8% Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 (40.0)% (30.0)% (20.0)% (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 Q3 2022 Supplemental Financial Information 7

Global Storage Volume (1) Global RIM Corporate and Other Q1 2020 Q2 2020 Q3 2020 Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 500,000 550,000 600,000 650,000 700,000 Q1 2020 Q2 2020 Q3 2020 Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 Global RIM 703,422 703,596 705,770 705,527 707,608 711,549 722,582 721,945 723,331 725,665 727,496 Corporate and Other 3,501 3,529 3,478 3,707 3,734 4,223 4,250 4,301 4,322 4,336 4,715 Total Storage Volume 706,923 707,126 709,247 709,233 711,342 715,772 726,831 726,246 727,653 730,001 732,211 Business acquisitions during the quarter (2) 2,678 1,980 272 — — 5,020 10,743 — — — 143 (1) Storage volumes presented have been recast to align with the presentation of the corresponding revenues. (2) Volume acquired through acquisition in the quarter, net of deconsolidation; this is included in Total Storage Volume. Section III - Operational Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 8

Quarterly Operating Performance Y/Y % Change Q3 2022 Q2 2022 Q3 2021 Reported Constant Currency Organic Growth (1) Global RIM Business Storage Rental $650,141 $649,771 $633,403 2.6% 6.6% 7.1% Service 440,961 420,705 364,440 21.0% 25.3% 25.6% Total Revenues $1,091,102 $1,070,476 $997,843 9.3% 13.4% 13.9% Adjusted EBITDA $483,862 $469,368 $435,904 Adjusted EBITDA Margin 44.3 % 43.8 % 43.7 % Global Data Center Business Storage Rental $96,328 $89,768 $72,411 33.0% 37.3% 32.6% Service 3,981 10,320 16,176 (75.4)% (73.4)% (74.3)% Total Revenues $100,309 $100,088 $88,587 13.2% 17.9% 13.3% Adjusted EBITDA $42,660 $42,307 $35,097 Adjusted EBITDA Margin 42.5 % 42.3 % 39.6 % Corporate and Other Business Storage Rental $13,900 $13,587 $12,800 8.6% 11.1% 8.7% Service 81,634 105,383 30,918 164.0% 175.5% 26.9% Total Revenues $95,534 $118,970 $43,718 118.5% 126.7% 21.5% Adjusted EBITDA $(57,088) $(56,969) $(53,232) Total Consolidated Storage Rental $760,370 $753,126 $718,614 5.8% 9.8% 9.7% Service $526,575 536,408 411,534 28.0% 32.8% 21.8% Total Revenues $1,286,945 $1,289,534 $1,130,148 13.9% 18.2% 14.1% Adjusted EBITDA $469,434 $454,706 $417,769 Adjusted EBITDA Margin 36.5 % 35.3 % 37.0 % (1) Constant Currency and excluding impact from business acquisitions and divestitures. Section III - Operational Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 9

Year to Date Operating Performance Y/Y % Change YTD 2022 YTD 2021 Reported Constant Currency Organic Growth (1) Global RIM Business Storage Rental $1,949,999 $1,883,967 3.5% 6.5% 6.0% Service 1,260,470 1,087,118 15.9% 19.2% 18.7% Total Revenues $3,210,469 $2,971,085 8.1% 11.1% 10.7% Adjusted EBITDA $1,402,025 $1,263,277 Adjusted EBITDA Margin 43.7 % 42.5 % Global Data Center Business Storage Rental $273,547 $210,805 29.8% 32.7% 27.7% Service 23,837 25,867 (7.8)% (1.5)% (3.5)% Total Revenues $297,384 $236,672 25.7% 29.1% 24.3% Adjusted EBITDA $126,944 $98,961 Adjusted EBITDA Margin 42.7 % 41.8 % Corporate and Other Business Storage Rental $41,019 $50,170 (18.2)% (17.4)% 8.5% Service 275,653 74,017 272.4% 285.4% 42.4% Total Revenues $316,672 $124,187 155.0% 161.3% 31.1% Adjusted EBITDA $(173,835) $(158,273) Total Consolidated Storage Rental $2,264,566 $2,144,942 5.6% 8.5% 8.2% Service 1,559,959 1,187,002 31.4% 35.3% 19.7% Total Revenues $3,824,525 $3,331,944 14.8% 18.0% 12.4% Adjusted EBITDA $1,355,134 $1,203,965 Adjusted EBITDA Margin 35.4 % 36.1 % (1) Constant Currency and excluding impact from business acquisitions and divestitures. Section III - Operational Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 10

Condensed Consolidated Balance Sheets 9/30/2022 12/31/2021 ASSETS Current Assets: Cash and Cash Equivalents $155,223 $255,828 Accounts Receivable, Net 1,133,596 961,419 Prepaid Expenses and Other 268,030 224,020 Total Current Assets $1,556,849 $1,441,267 Property, Plant and Equipment: Property, Plant and Equipment $8,794,078 $8,647,303 Less: Accumulated Depreciation (4,063,636) (3,979,159) Property, Plant and Equipment, Net $4,730,442 $4,668,144 Other Assets, Net: Goodwill $4,831,306 $4,463,531 Customer and Supplier Relationships and Other Intangible Assets 1,444,924 1,181,043 Operating Lease Right-of-Use Assets 2,556,253 2,314,422 Other 574,942 381,624 Total Other Assets, Net $9,407,425 $8,340,620 Total Assets $15,694,716 $14,450,031 LIABILITIES AND EQUITY Current Liabilities: Current Portion of Long-term Debt $81,275 $309,428 Accounts Payable 432,384 369,145 Accrued Expenses and Other Current Liabilities 929,566 1,032,537 Deferred Revenue 282,687 307,470 Total Current Liabilities $1,725,912 $2,018,580 Long-term Debt, Net of Current Portion 10,228,846 8,962,513 Long-term Operating Lease Liabilities, Net of Current Portion 2,405,751 2,171,472 Other Long-term Liabilities 398,830 144,053 Deferred Income Taxes 307,717 223,934 Redeemable Noncontrolling Interests 93,821 72,411 Total Long-term Liabilities $13,434,965 $11,574,383 Total Liabilities $15,160,877 $13,592,963 Equity Total Equity $533,839 $857,068 Total Liabilities and Equity $15,694,716 $14,450,031 Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 11

Quarterly Condensed Consolidated Statements of Operations Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change Revenues: Storage Rental $760,370 $753,126 1.0 % $718,614 5.8 % Service 526,575 536,408 (1.8) % 411,534 28.0 % Total Revenues $1,286,945 $1,289,534 (0.2) % $1,130,148 13.9 % Operating Expenses: Cost of Sales (excluding Depreciation and Amortization) $546,041 $556,476 (1.9) % $481,663 13.4 % Selling, General and Administrative 285,299 295,394 (3.4) % 241,596 18.1 % Depreciation and Amortization 175,077 178,254 (1.8) % 174,818 0.1 % Acquisition and Integration Costs 5,554 16,878 (67.1) % 1,138 n/a Restructuring Charges 3,382 — — 50,432 (93.3) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (14,170) (51,249) (72.4) % (935) n/a Total Operating Expenses $1,001,183 $995,753 0.5 % $948,712 5.5 % Operating Income $285,762 $293,781 (2.7) % $181,436 57.5 % Interest Expense, Net 121,767 115,057 5.8 % 103,809 17.3 % Other (Income) Expense, Net (52,870) (41,217) 28.3 % (18,501) n/a Net Income (Loss) Before Provision (Benefit) for Income Taxes $216,865 $219,941 (1.4) % $96,128 n/a Provision (Benefit) for Income Taxes 23,934 18,083 32.4 % 28,017 (14.6) % Net Income (Loss) $192,931 $201,858 (4.4) % $68,111 n/a Less: Net Income (Loss) Attributable to Noncontrolling Interests 767 1,777 (56.8) % 428 79.2 % Net Income (Loss) Attributable to Iron Mountain Incorporated $192,164 $200,081 (4.0) % $67,683 n/a Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated: Basic $0.66 $0.69 (4.3) % $0.23 n/a Diluted $0.66 $0.68 (2.9) % $0.23 n/a Weighted Average Common Shares Outstanding - Basic 290,937 290,756 0.1 % 289,762 0.4 % Weighted Average Common Shares Outstanding - Diluted 292,552 292,487 — 291,482 0.4 % Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 12

Year to Date Condensed Consolidated Statements of Operations YTD 2022 YTD 2021 % Change Revenues: Storage Rental $2,264,566 $2,144,942 5.6 % Service 1,559,959 1,187,002 31.4 % Total Revenues $3,824,525 $3,331,944 14.8 % Operating Expenses: Cost of Sales (excluding Depreciation and Amortization) $1,649,139 $1,408,151 17.1 % Selling, General and Administrative 861,416 760,098 13.3 % Depreciation and Amortization 536,946 507,145 5.9 % Acquisition and Integration Costs 38,093 3,415 n/a Restructuring Charges 3,382 129,686 (97.4) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (66,124) (134,321) (50.8) % Total Operating Expenses $3,022,852 $2,674,174 13.0 % Operating Income $801,673 $657,770 21.9 % Interest Expense, Net 351,266 313,451 12.1 % Other (Income) Expense, Net (38,186) (200,018) (80.9) % Net Income (Loss) Before Provision (Benefit) for Income Taxes $488,593 $544,337 (10.2) % Provision (Benefit) for Income Taxes 52,097 153,073 (66.0) % Net Income (Loss) $436,496 $391,264 11.6 % Less: Net Income (Loss) Attributable to Noncontrolling Interests 1,952 2,693 (27.5) % Net Income (Loss) Attributable to Iron Mountain Incorporated $434,544 $388,571 11.8 % Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated: Basic $1.49 $1.34 11.2 % Diluted $1.49 $1.34 11.2 % Weighted Average Common Shares Outstanding - Basic 290,673 289,255 0.5 % Weighted Average Common Shares Outstanding - Diluted 292,294 290,697 0.5 % Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 13

Quarterly Reconciliation of Net Income (Loss) to Adjusted EBITDA Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change Net Income (Loss) $192,931 $201,858 (4.4) % $68,111 n/a Add / (Deduct): Interest Expense, Net 121,767 115,057 5.8 % 103,809 17.3 % Provision (Benefit) for Income Taxes 23,934 18,083 32.4 % 28,017 (14.6) % Depreciation and Amortization 175,077 178,254 (1.8) % 174,818 0.1 % Acquisition and Integration Costs 5,554 16,878 (67.1) % 1,138 n/a Restructuring Charges 3,382 — — 50,432 (93.3) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (Including Real Estate) (14,170) (51,249) (72.4) % (935) n/a Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (56,226) (46,103) 22.0 % (21,517) n/a Stock-Based Compensation Expense 14,326 20,256 (29.3) % 12,644 13.3 % Our Share of Adjusted EBITDA Reconciling Items from our Unconsolidated Joint Ventures 2,859 1,672 71.0 % 1,252 n/a Adjusted EBITDA $469,434 $454,706 3.2 % $417,769 12.4 % Year to Date Reconciliation of Net Income (Loss) to Adjusted EBITDA YTD 2022 YTD 2021 % Change Net Income (Loss) $436,496 $391,264 11.6 % Add / (Deduct): Interest Expense, Net 351,266 313,451 12.1 % Provision (Benefit) for Income Taxes 52,097 153,073 (66.0) % Depreciation and Amortization 536,946 507,145 5.9 % Acquisition and Integration Costs 38,093 3,415 n/a Restructuring Charges 3,382 129,686 (97.4) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (Including Real Estate) (66,124) (134,321) (50.8) % Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (48,814) (209,001) (76.6) % Stock-Based Compensation Expense 45,923 45,913 — Our Share of Adjusted EBITDA Reconciling Items from our Unconsolidated Joint Ventures 5,869 3,340 75.7 % Adjusted EBITDA $1,355,134 $1,203,965 12.6 % Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 14

Quarterly Reconciliation of Reported Earnings per Share to Adjusted Earnings per Share Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change Reported EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $0.66 $0.68 (4.0) % $0.23 n/a Add / (Deduct): Acquisition and Integration Costs 0.02 0.06 (68.4) % — — Restructuring Charges 0.01 — — 0.17 (93.2) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (0.05) (0.18) (73.1) % (0.01) n/a Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (0.19) (0.16) 20.1 % (0.07) n/a Stock-Based Compensation Expense 0.05 0.07 (30.0) % 0.04 22.4 % Tax Impact of Reconciling Items and Discrete Tax Items (1) (0.01) (0.03) (54.2) % 0.02 n/a Net Income (Loss) Attributable to Noncontrolling Interests — 0.01 (100.0) % — — Adjusted EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $0.48 $0.46 4.3 % $0.40 20.0 % Year to Date Reconciliation of Reported Earnings per Share to Adjusted Earnings per Share YTD 2022 YTD 2021 % Change Reported EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $1.49 $1.34 10.6 % Add / (Deduct): Acquisition and Integration Costs 0.13 0.01 n/a Restructuring Charges 0.01 0.45 (97.4) % Amortization Related to the Write-Off of Certain Customer Relationship Intangible Assets 0.02 — — (Gain) Loss on Disposal/Write-Down of PP&E, Net (0.22) (0.46) (51.5) % Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (0.17) (0.72) (76.8) % Stock-Based Compensation Expense 0.16 0.16 — Tax Impact of Reconciling Items and Discrete Tax Items (1) (0.09) 0.31 n/a Net Income (Loss) Attributable to Noncontrolling Interests 0.01 0.01 (27.9) % Adjusted EPS - Fully Diluted from Net Income (Loss) Attributable to Iron Mountain Incorporated $1.34 $1.09 22.9 % (1) The difference between our effective tax rates and our structural tax rate (or adjusted effective tax rates) for the three months ended September 30, 2022 and 2021 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 quarter ended September 30, 2022, quarter ended June 30, 2022, quarter ended September 30, 2021, and year-to-date periods ended September 30, 2022 and 2021 was 16.5%, respectively. The Tax Impact of Reconciling Items and Discrete Tax Items is calculated using the current quarter’s estimate of the annual structural tax rate for the full year. This may result in the current period adjustment plus prior reported quarterly adjustments not summing to the full year adjustment. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 15

Quarterly Reconciliation of Net Income (Loss) to FFO and AFFO Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change Net Income (Loss) $192,931 $201,858 (4.4) % $68,111 n/a Add / (Deduct): Real Estate Depreciation (1) 74,652 75,008 (0.5) % 79,463 (6.1) % (Gain) Loss on Sale of Real Estate, Net of Tax (15,666) (48,978) (68.0) % 748 n/a Data Center Lease-Based Intangible Asset Amortization (2) 3,687 4,040 (8.7) % 10,458 (64.7) % FFO (Nareit) $255,604 $231,928 10.2 % $158,780 61.0 % Add / (Deduct): Acquisition and Integration Costs 5,554 16,878 (67.1) % 1,138 n/a Restructuring Charges 3,382 — — 50,432 (93.3) % Loss (Gain) on Disposal/Write-Down of PP&E, Net (Excluding Real Estate) 2,616 (2,270) n/a (1,668) n/a Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (56,226) (46,103) 22.0 % (21,517) n/a Stock-Based Compensation Expense 14,326 20,256 (29.3) % 12,644 13.3 % Real Estate Financing Lease Depreciation 3,020 3,427 (11.9) % 3,740 (19.3) % Tax Impact of Reconciling Items and Discrete Tax Items (3) (5,184) (8,250) 37.2 % 5,304 n/a Our Share of FFO (Normalized) Reconciling Items from our Unconsolidated Joint Ventures 223 374 (40.4) % (17) n/a FFO (Normalized) $223,315 $216,240 3.3 % $208,836 6.9 % Per Share Amounts (Fully Diluted Shares): FFO (Nareit) $0.87 $0.79 10.1 % $0.55 59.6 % FFO (Normalized) $0.76 $0.74 2.7 % $0.72 5.6 % Weighted Average Common Shares Outstanding - Basic 290,937 290,756 0.1 % 289,762 0.4 % Weighted Average Common Shares Outstanding - Diluted 292,552 292,487 — 291,482 0.4 % (1) Includes depreciation expense related to owned real estate assets (land improvements, buildings, building improvements, leasehold of 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 and (ii) other discrete tax items. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 16

Quarterly Reconciliation of Net Income (Loss) to FFO and AFFO (Continued) Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change FFO (Normalized) $223,315 $216,240 3.3 % $208,836 6.9 % Add / (Deduct): Non-Real Estate Depreciation 36,458 37,667 (3.2) % 37,128 (1.8) % Amortization Expense (1) 46,764 48,332 (3.2) % 36,361 28.6 % Amortization of Deferred Financing Costs 4,472 3,454 29.5 % 4,027 11.1 % Revenue Reduction Associated with Amortization of Customer Inducements and Above- and Below-Market Leases 1,851 1,821 1.7 % 2,251 (17.7) % Non-Cash Rent Expense (Income) 5,522 4,384 26.0 % 3,722 48.4 % Reconciliation to Normalized Cash Taxes 7,366 (9,422) n/a 8,133 (9.4) % Our Share of AFFO Reconciling Items from our Unconsolidated Joint Ventures 1,193 857 39.3 % 1,021 16.9 % Less: Recurring Capital Expenditures 38,972 32,399 20.3 % 37,995 2.6 % AFFO $287,971 $270,934 6.3 % $263,484 9.3 % Per Share Amounts (Fully Diluted Shares): AFFO Per Share $0.98 $0.93 6.3 % $0.90 8.9 % Weighted Average Common Shares Outstanding - Basic 290,937 290,756 0.1 % 289,762 0.4 % Weighted Average Common Shares Outstanding - Diluted 292,552 292,487 — 291,482 0.4 % (1) Includes Customer Relationship Value, intake costs, acquisition of customer and supplier relationships, and other intangibles. Excludes amortization of capitalized commissions of $10.5M, $9.8M, and $7.7M in Q3 2022, Q2 2022, and Q3 2021, respectively. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 17

Year to Date Reconciliation of Net Income (Loss) to FFO and AFFO YTD 2022 YTD 2021 % Change Net Income (Loss) $436,496 $391,264 11.6 % Add / (Deduct): Real Estate Depreciation (1) 228,993 230,294 (0.6) % (Gain) Loss on Sale of Real Estate, Net of Tax (64,430) (106,033) (39.2) % Data Center Lease-Based Intangible Asset Amortization (2) 11,850 31,423 (62.3) % FFO (Nareit) $612,909 $546,948 12.1 % Add / (Deduct): Acquisition and Integration Costs 38,093 3,415 n/a Restructuring Charges 3,382 129,686 (97.4) % (Gain) Loss on Disposal/Write-Down of PP&E, Net (Excluding Real Estate) (573) (2,890) (80.2) % Other (Income) Expense, Net, Excluding our Share of Losses (Gains) from our Unconsolidated Joint Ventures (48,814) (209,001) (76.6) % Stock-Based Compensation Expense 45,923 45,913 — Real Estate Financing Lease Depreciation 10,227 10,791 (5.2) % Tax Impact of Reconciling Items and Discrete Tax Items (3) (26,090) 65,120 n/a Our Share of FFO (Normalized) Reconciling Items from our Unconsolidated Joint Ventures 577 (30) n/a FFO (Normalized) $635,634 $589,952 7.7 % Per Share Amounts (Fully Diluted Shares): FFO (Nareit) $2.10 $1.88 11.4 % FFO (Normalized) $2.17 $2.03 7.2 % Weighted Average Common Shares Outstanding - Basic 290,673 289,255 0.5 % Weighted Average Common Shares Outstanding - Diluted 292,294 290,697 0.5 % (1) Includes depreciation expense related to owned real estate assets (land improvements, buildings, building improvements, leasehold of 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 and (ii) other discrete tax items. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 18

Year to Date Reconciliation of Net Income (Loss) to FFO and AFFO (continued) YTD 2022 YTD 2021 % Change FFO (Normalized) $635,634 $589,952 7.7 % Add / (Deduct): Non-Real Estate Depreciation 111,406 106,185 4.9 % Amortization Expense (1) 145,590 106,097 37.2 % Amortization of Deferred Financing Costs 13,536 12,470 8.6 % Revenue Reduction Associated with Amortization of Customer Inducements and Above- and Below-Market Leases 5,532 6,578 (15.9) % Non-Cash Rent Expense (Income) 13,033 13,091 (0.4) % Reconciliation to Normalized Cash Taxes 1,405 10,080 (86.1) % Our Share of AFFO Reconciling Items from our Unconsolidated Joint Ventures 3,160 2,902 8.9 % Less: Recurring Capital Expenditures 106,156 102,487 3.6 % AFFO $823,140 $744,868 10.5 % Per Share Amounts (Fully Diluted Shares): AFFO Per Share $2.82 $2.56 9.9 % Weighted Average Common Shares Outstanding - Basic 290,673 289,255 0.5 % Weighted Average Common Shares Outstanding - Diluted 292,294 290,697 0.5 % (1) Includes Customer Relationship Value, intake costs, acquisition of customer and supplier relationships, and other intangibles. Excludes amortization of capitalized commissions of $28.9M and $22.4M in YTD 2022 and YTD 2021, respectively. Section IV - Balance Sheets, Statements of Operations and Reconciliations investors.ironmountain.com Q3 2022 Supplemental Financial Information 19

Quarterly Storage Rental and Service Business Detail Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change Storage Rental Business Detail Total Storage Rental Revenue $760,370 $753,126 1.0 % $718,614 5.8 % Plus: Terminations/Permanent Withdrawal Fees 8,452 8,739 (3.3) % 5,612 50.6 % Total Revenue from Adjusted Storage Rental Activities $768,821 $761,866 0.9 % $724,225 6.2 % Less: Storage Rental Expenses Storage Rent 105,991 103,420 2.5 % 104,513 1.4 % Other Facility Costs 103,761 97,825 6.1 % 87,613 18.4 % Storage Rental Labor 7,302 6,953 5.0 % 7,120 2.6 % Other Storage Rental Expenses 11,150 10,366 7.6 % 8,206 35.9 % Storage Rental Cost of Sales $228,205 $218,563 4.4 % $207,452 10.0 % Storage Rental Gross Profit $540,617 $543,302 (0.5) % $516,773 4.6 % Storage Rental Gross Margin 70.3 % 71.3 % (100) bps 71.4 % (110) bps Service Business Detail Total Service Revenue $526,575 $536,408 (1.8) % $411,534 28.0 % Less: Terminations/Permanent Withdrawal Fees 8,452 8,739 (3.3) % 5,612 50.6 % Total Revenue from Adjusted Service Activities $518,124 $527,669 (1.8) % $405,922 27.6 % Less: Service Expenses Service Rent 4,051 4,273 (5.2) % 2,838 42.8 % Other Facility Costs 9,585 8,278 15.8 % 7,508 27.7 % Service Labor 192,435 196,506 (2.1) % 183,165 5.1 % Other Service Expenses 111,765 128,856 (13.3) % 80,699 38.5 % Service Cost of Sales $317,836 $337,913 (5.9) % $274,211 15.9 % Service Gross Profit $200,288 $189,756 5.6 % $131,712 52.1 % Service Gross Margin 38.7 % 36.0 % 270 bps 32.4 % 630 bps Section V - Storage and Service Reconciliation investors.ironmountain.com Q3 2022 Supplemental Financial Information 20

Year to Date Storage Rental and Service Business Detail YTD 2022 YTD 2021 % Change Storage Rental Business Detail Total Storage Rental Revenue $2,264,566 $2,144,942 5.6 % Plus: Terminations/Permanent Withdrawal Fees 25,554 19,490 31.1 % Total Revenue from Adjusted Storage Rental Activities $2,290,120 $2,164,432 5.8 % Less: Storage Rental Expenses Storage Rent 313,702 301,529 4.0 % Other Facility Costs 304,358 262,273 16.0 % Storage Rental Labor 20,996 21,932 (4.3) % Other Storage Rental Expenses 31,677 30,936 2.4 % Storage Rental Cost of Sales $670,733 $616,671 8.8 % Storage Rental Gross Profit $1,619,387 $1,547,761 4.6 % Storage Rental Gross Margin 70.7 % 71.5 % (80) bps Service Business Detail Total Service Revenue $1,559,959 $1,187,002 31.4 % Less: Terminations/Permanent Withdrawal Fees 25,554 19,490 31.1 % Total Revenue from Adjusted Service Activities $1,534,406 $1,167,512 31.4 % Less: Service Expenses Service Rent 12,193 8,891 37.1 % Other Facility Costs 25,249 20,760 21.6 % Service Labor 583,702 556,833 4.8 % Other Service Expenses 357,262 204,996 74.3 % Service Cost of Sales $978,406 $791,480 23.6 % Service Gross Profit $556,000 $376,032 47.9 % Service Gross Margin 36.2 % 32.2 % 400 bps Section V - Storage and Service Reconciliation investors.ironmountain.com Q3 2022 Supplemental Financial Information 21

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 6/30/2022 (2) 252 23,782 1,124 70,829 1,376 94,611 Additions & Expansions — — 29 2,426 29 2,426 Dispositions & Move Outs (3) (150) (13) (191) (16) (341) Total as of 9/30/2022 (3) 249 23,632 1,140 73,064 1,389 96,696 Total % 17.9 % 24.4 % 82.1 % 75.6 % Top Five Markets Owned, United States (in Sq. Ft.) Top Five Markets Owned, International (in Sq. Ft.) Northern New Jersey 1,947 Paris, France 807 Chicago 1,282 Montreal, Canada 552 Boston 1,258 Mexico City, Mexico 452 Dallas 966 Toronto, Canada 434 Houston 917 Lima, Peru 434 Facility Lease Expirations (4) (% of total square feet subject to lease) 3.8% 5.1% 3.8% 4.5% 3.4% 2.3% 2.7% 5.0% 4.4% 65.0% 2022 2023 2024 2025 2026 2027 2028 2029 2030 Thereafter Weighted-Average Remaining Operating Lease Obligation: 11.7 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 11 owned data center facilities and 5 leased data center facilities with 2.7M Sq. Ft. and 0.6M Sq. Ft., respectively. (4) Includes financing and operating lease obligations. Section VI - Real Estate Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 22

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 2022 89 1.9 0.6% 6,638 1.7% 2023 593 24.4 8.1% 72,901 18.5% 2024 293 14.1 4.6% 36,906 9.4% 2025 234 29.2 9.6% 64,703 16.4% 2026 70 21.2 7.0% 36,318 9.2% 2027 31 8.4 2.8% 17,862 4.5% 2028 20 46.8 15.4% 54,743 13.9% Thereafter 22 157.1 51.9% 104,309 26.4% Total 1,352 303.1 100.0% $394,381 100.0% WALE: 5.1 years Data Center Leasing Activity Summary Q3 2022 YTD 2022 Transaction Count GAAP MRR kW $ / kW / Month Transaction Count GAAP MRR kW $ / kW / Month New/expansion leases signed 36 $750 6,901 $109 148 $5,251 52,996 $99 New Built to Suit leases signed — — — — 2 1,346 72,000 19 Commenced leases 43 1,332 14,332 93 127 2,870 24,286 118 Renewed leases 167 1,870 7,774 241 440 4,741 19,670 241 Churn 0.6% 3.2% Cash Mark to Market 1.9% 1.8% GAAP Mark to Market 4.6% 3.9% VA-2 Data Center Rendering Section VII - Data Center Customer and Portfolio Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 23

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 78.8% — — 14.2 78.8% Phoenix AZP-1 41.0 100.0% — — 41.0 100.0% AZP-2 23.0 100.0% 1.0 — 24.0 95.8% Scottsdale AZS-1 5.7 47.6% — — 5.7 47.6% Denver DEN-1 11.3 54.3% — — 11.3 54.3% New Jersey NJE-1 15.1 100.0% 1.2 8.3% 16.3 93.3% Northern Virginia VA-1 12.4 100.0% — — 12.4 100.0% VA-2 22.0 100.0% — — 22.0 100.0% Amsterdam AMS-1 13.1 92.1% — — 13.1 92.1% London LON-1 8.7 99.2% — — 8.7 99.2% Frankfurt FRA-1 9.0 100.0% — — 9.0 100.0% FRA-2 4.6 100.0% — — 4.6 100.0% Singapore SIN-1 6.75 100.0% — — 6.75 100.0% India Web Werks JV 1.5 40.9% — — 1.5 40.9% Total Data Center Properties 188.4 93.0% 2.2 4.5% 190.6 92.0% Total Potential Capacity - Megawatts Q3 2022 Q3 2021 Leasable 190.6 156.6 Under Construction 173.7 60.4 Held for Development 303.8 261.6 Total Data Center Portfolio 668.1 478.6 Section VII - Data Center Customer and Portfolio Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 24

Data Center Expansion and Development Activity Project / Facilities MW Under Construction MW Pre- leased % Pre- Leased Investment in Q3 2022 ($M) Cumulative Investment ($M) Total Expected Investment ($M) Expected Completion Expected Stabilization MW Held for Development Data Center Expansion Amsterdam AMS-1 Phase 4 5.0 — — $5.9 $14.3 $45.0 Q1 2024 Q1 2025 4.6 Phoenix AZP-2 Phase 5 6.0 6.0 100.0% $8.1 $70.4 $95.6 Q4 2023 Q4 2023 — AZP-2 Phase 6 6.0 3.0 50.0% $13.9 $21.1 $41.0 Q1 2023 Q4 2023 — AZP-2 Phase 7 4.5 4.5 100.0% $8.5 $8.5 $35.0 Q1 2023 Q1 2023 7.5 Northern Virginia VA-2 Phase 4 14.0 8.0 57.1% $17.3 $23.0 $105.0 Q2 2023 Q2 2024 — New Jersey NJE-1 Phase 4 0.5 0.5 100.0% $0.4 $2.3 $4.8 Q4 2022 Q4 2022 — NJE-1 Phase 5 4.0 2.5 62.5% $4.6 $8.8 $34.0 Q1 2023 Q1 2024 4.8 Frankfurt FRA-2 Phase 2 6.0 — — $7.8 $8.2 $61.5 Q2 2023 Q2 2024 — India Web Werks JV 0.7 — — — — — 1.6 All Other Facilities — — — — — — 14.3 Total Expansion 46.7 24.5 52.5% $66.5 $156.5 $422.0 32.8 New Development Phoenix AZP-3 — — — — — — 36.0 Amsterdam AMS-2 — — — — — — 10.6 Chicago CHI-2 — — — — — — 36.0 Frankfurt (1) FRA-1 Phase 2 9.0 9.0 100.0% — — — Q2 2023 Q4 2024 — FRA-1 Phase 3 9.0 9.0 100.0% — — — Q2 2023 Q2 2027 — London LON-2 Phase 1 9.0 9.0 100.0% $20.8 $49.3 $133.4 Q2 2023 Q4 2023 — LON-2 Phase 2 9.0 9.0 100.0% $6.5 $10.8 $60.0 Q4 2023 Q4 2024 — LON-2 Phase 3 9.0 9.0 100.0% $0.2 $0.2 $60.0 Q2 2024 Q4 2028 — Northern Virginia (2) VA-4 32.0 32.0 100.0% $0.7 $0.7 $96.2 Q3 2025 Q3 2025 — VA-5 40.0 40.0 100.0% $0.6 $0.6 $109.5 Q2 2025 Q2 2025 — VA Future Phases — — — — — — 150.0 India (3) Web Werks JV 10.0 — — — — — 38.5 Total New Development 127.0 117.0 92.1% $28.8 $61.6 $459.1 271.0 Total Development 173.7 141.5 81.5% $95.3 $218.1 $881.1 303.8 (1) FRA-1 is an unconsolidated joint venture; construction costs are funded by the Joint Venture with Iron Mountain managing the construction. (2) VA-4/5 is a consolidated joint venture; construction costs are funded by the Joint Venture with Iron Mountain managing the construction. (3) Represents an unconsolidated joint venture in India; operating three facilities in three markets, and with land parcels in a further two markets. Section VII - Data Center Customer and Portfolio Metrics investors.ironmountain.com Q3 2022 Supplemental Financial Information 25

Capitalization Revolving Credit Facility and Term Loan A Total Market Capitalization as of 9/30/2022 Capacity $2,493,750 # of Shares Outstanding 290,688 Outstanding $1,133,750 Share Price as of 09/30/22 $43.97 Letters of Credit $3,779 Total Market Capitalization $12,781,549 Remaining Capacity $1,356,221 Net Debt (1) $10,240,058 Interest Rate Spread (Prime) 0.75 % Total Enterprise Value $23,021,607 Interest Rate Spread (SOFR) 1.85 % Net Debt to Total Enterprise Value 44.5 % Weighted Average Interest Rate 4.71 % Adjusted EBITDA to Interest Expense 3.9x Maturity Date 3/18/2027 Total Enterprise Value to Adjusted EBITDA (2) 12.9x Credit Facility Fixed Charge Coverage Ratio 2.5x Net Total Lease-Adjusted Leverage Ratio 5.2x Fixed vs. Floating Rate Debt 79% 21% Fixed Rate Debt Floating Rate Debt Credit Rating S&P Moody's Corporate BB- Ba3 Senior Credit Facility BB Ba3 Outlook Stable Stable Latest Update 12/10/2021 12/13/2021 Total Debt Weighted Average Rates Weighted Average Interest 5.0 % Weighted Average Maturity 6.3 Years USD denominated 86 % Debt Maturity Profile ($ in Millions) (3) $25 $28 $198 $784 $897 $2,078 $1,325 $1,000 $1,300 $1,100 $1,350 Senior Secured Credit Facility Bi-Lateral Loans AUD Term Loan B A/R Securitization USD Term Loan B Mortgage Securitization Senior Unsecured Notes 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 (1) Net debt is calculated as current portion of long-term debt of $81.3M plus long-term debt net of current portion of $10,228.8M plus deferred financing costs of $85.2M less cash and cash equivalents of $155.2M. (2) Total Enterprise Value to Adjusted EBITDA is calculated on a trailing twelve-month basis. (3) Excludes Deferred Financing Costs, Financing Leases, Notes Payable and Other. Section VIII - Capitalization and Debt Maturity Profile investors.ironmountain.com Q3 2022 Supplemental Financial Information 26

Quarterly Capital Expenditures Q3 2022 Q2 2022 Q/Q % Change Q3 2021 Y/Y % Change Growth: Data Center $212,200 $101,655 n/a $72,651 n/a Real Estate 47,519 39,564 20.1 % 21,033 n/a Innovation and Other 9,850 14,938 (34.1) % 6,302 56.3 % Total Growth Capital Expenditures $269,569 $156,158 72.6 % $99,986 n/a Recurring: Real Estate $20,622 $16,131 27.8 % $13,587 51.8 % Non-Real Estate 14,608 13,058 11.9 % 20,497 (28.7) % Data Center 3,742 3,210 16.6 % 3,912 (4.3) % Total Recurring Capital Expenditures $38,972 $32,399 20.3 % $37,995 2.6 % Total Growth and Recurring Capital Expenditures $308,541 $188,557 63.6 % $137,981 n/a Net Change in Prepaid and Accrued Capital Expenditures (41,960) (19,388) n/a (14,591) n/a Total Cash Paid for Growth and Recurring Capital Expenditures $266,581 $169,170 57.6 % $123,390 n/a Year to Date Capital Expenditures YTD 2022 YTD 2021 % Change Growth: Data Center $396,015 $209,097 89.4 % Real Estate 114,374 60,558 88.9 % Innovation and Other 30,808 15,445 99.5 % Total Growth Capital Expenditures $541,197 $285,100 89.8 % Recurring: Real Estate $44,294 $43,398 2.1 % Non-Real Estate 52,442 52,153 0.6 % Data Center 9,420 6,936 35.8 % Total Recurring Capital Expenditures $106,156 $102,487 3.6 % Total Growth and Recurring Capital Expenditures $647,353 $387,587 67.0 % Net Change in Prepaid and Accrued Capital Expenditures (50,552) 31,389 n/a Total Cash Paid for Growth and Recurring Capital Expenditures $596,801 $418,976 42.4 % TTM Recurring Capex as a % of Revenue (excl. Data Center) 3.7% 3.2% 3.2% 3.0% 3.0% Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 TTM Data Center Recurring CapEx as a % of Data Center Revenue 4.8% 4.1% 4.2% 4.3% 4.1% Q3 2021 Q4 2021 Q1 2022 Q2 2022 Q3 2022 Section IX - Capital Expenditures investors.ironmountain.com Q3 2022 Supplemental Financial Information 27

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). Acquisition and Integration Costs: Acquisition and Integration Costs represent 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, facility upgrade and system integration costs (collectively, "Acquisition and Integration Costs"). Acquisition and Integration Costs do not include costs associated with the formation of joint ventures or costs associated with the acquisition of customer relationships. 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 charges; (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 (income) expense, net; (vi) Stock-based compensation expense; and (vii) 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. 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 charges; (iii) (Gain) loss on disposal/write-down of property, plant and equipment, net (including real estate); (iv) Other (income) expense, net; and (v) Stock-based compensation expense. Adjusted EBITDA Margin is calculated by dividing Adjusted EBITDA by total revenues. We also show Adjusted EBITDA and Adjusted EBITDA Margin for each of our reportable operating segments under “Results of Operations – Segment Analysis” in the 10-Q/10-K. 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 EBITDA excludes both interest expense, net and the provision (benefit) for income taxes. These expenses are associated with our capitalization and tax structures, which we do not consider when evaluating the operating profitability of our core operations. Adjusted EBITDA also does not include depreciation and amortization expenses, in order to eliminate the impact of capital investments, which we evaluate by comparing capital expenditures to incremental revenue generated and as a percentage of total revenues. Adjusted EBITDA and Adjusted EBITDA Margin 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, net income (loss) or cash flows from operating activities (as determined in accordance with GAAP). Adjusted Funds From Operations, or AFFO: Adjusted funds from operations (“AFFO”) is defined as FFO (Normalized) (1) excluding (i) non-cash rent expense (income), (ii) depreciation on non-real estate assets, (iii) amortization expense associated with customer relationship value (CRV), intake costs, acquisitions of customer and supplier relationships and other intangibles, (other than capitalized internal commissions), (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 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). AFFO per share: AFFO divided by weighted-average fully-diluted shares outstanding. Funds From Operations, or FFO (Nareit), and FFO (Normalized): Funds from operations ("FFO") is defined by the National Association of Real Estate Investment Trusts (“Nareit”) 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 and adjusting for our share of reconciling items from our unconsolidated joint ventures from FFO (“FFO (Nareit)”). 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). Although Nareit has published a definition of FFO, 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 charges; (iii) Loss (gain) on disposal/write-down of property, plant and equipment, net (excluding real estate); (iv) Other expense (income), net; (v) Stock-based compensation expense; (vi) Real estate financing lease depreciation; and (vii) Tax impact of reconciling items and discrete tax items. Section X - Appendix and Definitions investors.ironmountain.com Q3 2022 Supplemental Financial Information 28

FFO (Normalized) per share: FFO (Normalized) divided by weighted-average fully-diluted shares outstanding. Other Definitions Business Segments Global Record and Information Management ("Global RIM") Business: Provides (i) storage of physical records and healthcare information services, vital records services, courier operations, and the collection, handling and disposal of sensitive documents (collectively, “Records Management”) for customers in 59 countries around the globe, (ii) storage and rotation of backup computer media as part of corporate disaster recovery plans, including service and courier operations (“Data Protection & Recovery”); server and computer backup services; and related services offerings (collectively, “Data Management”), (iii) Global Digital Solutions (“GDS”), which 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, (iv) secure shredding services through a combination of shredding facilities and mobile shredding units consisting of custom-built trucks, which is a natural extension of our hardcopy records management operations, completing the lifecycle of a record, and includes the scheduled pick-up of office records that customers accumulate in specially designed secure containers we provide (“Secure Shredding”), (v) 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”), and (vi) on-demand, valet storage for consumers (“Consumer Storage”) through a strategic partnership that utilizes 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 Business: Consists primarily of our Fine Arts and ALM businesses and other corporate items. Our Fine Arts business provides technical expertise in the handling, installation and storing of art (“Fine Arts”). Our ALM business provides hyperscale and corporate IT infrastructure managers with services and solutions that enable the decommissioning and disposition or sale of IT hardware and component assets. ALM services are enabled by: secure logistics and chain of custody practices, environmentally-responsible asset processing and recycling, and data sanitization and asset refurbishment services that enable value recovery through asset remarketing. Our ALM service focuses on protecting and eradicating customer data while maintaining strong, auditable, and transparent chain of custody practices. Our ALM business includes our legacy secure IT disposition business and our acquired ITRenew business (“ITRenew”). Corporate and Other Business 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 improvement of products and services and projects designed to increase our profitability. These expenditures are generally relatively small and discretionary in nature. We categorize our capital expenditures as follows: Growth Investment: Data Center - Expenditures primarily related to investments in new construction of data center facilities (including the acquisition of land and development of facilities) or capacity expansion in existing buildings. Real Estate - Expenditures primarily related to investments in land, buildings, building improvements, leasehold improvements and racking structures to grow our revenues or achieve operational efficiencies. Innovation & Other - Discretionary capital expenditures for significant new products and services, restructuring (including Project Summit), and integration of acquisitions. Recurring: 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. Data Center - Expenditures related to the upgrade or re-configuration of existing data center assets. Constant Currency: Adjusts results to normalize FX impacts across comparable periods. Section X - Appendix and Definitions investors.ironmountain.com Q3 2022 Supplemental Financial Information 29

Data Center Business Definitions Leaseable MW - Represents the amount of critical power capacity available for customer use, measured in megawatts. 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. Credit Facility Fixed Charge Coverage Ratio: Calculated as LTM Adjusted EBITDA plus rent expenses 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 EBITDA plus rent expenses. Organic Revenue Growth: Our organic revenue growth rate, which is a non-GAAP measure, 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: 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.: Storage revenue (or storage NOI) divided by the quarterly building Sq. Ft. average for storage products. Service Profit and Margin: The Gross Profit and Margin attributable to the worldwide service business. Calculated as follows: Total Revenues from Adjusted Service Activities - Service Cost of Sales = Service Gross Profit ($) / Total Revenues from Adjusted Service Activities = Service Gross Margin (%) Storage Net Operating Income, or Storage NOI: Storage NOI is defined as revenue from rental activities (storage rental revenue, termination fees and permanent withdrawal fees) less storage rental costs. Storage rental costs include facility costs (excluding rent), storage rental labor, other storage costs and allocated overhead. Storage NOI is commonly used in the REIT industry and enables investors to understand and value the income generated from the company’s real estate. Storage Profit and Margin: Gross Profit and Margin attributable to the worldwide storage business. Calculated as follows: Total Revenue from Adjusted Storage Rental Activities - Storage Rental Cost of Sales = Storage Rental Gross Profit ($) / 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 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 measured on an absolute basis in cubic feet. Formerly reported broken out by Records Management hardcopy records, data protection tapes, Consumer and Other, and Fine Art and Entertainment Services ("Adjacent Businesses"), measured on an absolute basis in cubic feet. Section X - Appendix and Definitions investors.ironmountain.com Q3 2022 Supplemental Financial Information 30