The components of our amortizable intangible assets at March 31, 2010 are as follows:

e.

Stock-Based Compensation

        We record stock-based compensation expense, utilizing the straight-line method, for the cost of stock options, restricted stock and shares issued under the employee stock purchase plan (together, "Employee Stock-Based Awards").

        Stock-based compensation expense, included in the accompanying consolidated statements of operations, for the three months ended March 31, 2009 and 2010 was $4,259 ($3,465 after tax or $0.02 per basic and diluted share) and $4,727 ($3,700 after tax or $0.02 per basic and diluted share), respectively, for Employee Stock-Based Awards.

        The benefits associated with the tax deductions in excess of recognized compensation cost are reported as a financing cash flow. This requirement reduces reported operating cash flows and increases reported financing cash flows. As a result, net financing cash flows included $545 and $613 for the three months ended March 31, 2009 and 2010, respectively, from the benefits of tax deductions in excess of recognized compensation cost. We used the short form method to calculate the Additional Paid-in Capital ("APIC") pool. The tax benefit of any resulting excess tax deduction increases the APIC pool. Any resulting tax deficiency is deducted from the APIC pool.

Stock Options

        Under our various stock option plans, options were granted with exercise prices equal to the market price of the stock on the date of grant. The majority of our options become exercisable ratably over a period of five years and generally have a contractual life of ten years, unless the holder's employment is terminated. Beginning in 2007, certain of the options we issue become exercisable ratably over a period of ten years and have a contractual life of 12 years, unless the holder's employment is terminated. As of March 31, 2010, ten-year vesting options represent 8.3% of total outstanding options. Our directors are considered employees for purposes of our stock option plans and stock option reporting.

11

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

        The weighted average fair value of options granted for the three months ended March 31, 2009 and 2010 was $6.43 and $8.61 per share, respectively. The values were estimated on the date of grant using the Black-Scholes option pricing model. The following table summarizes the weighted average assumptions used for grants in the respective period:

        Expected volatility was calculated utilizing daily historical volatility over a period that equates to the expected life of the option. The risk-free interest rate was based on the U.S. Treasury interest rates whose term is consistent with the expected life of the stock options. Beginning in the first quarter of 2010, expected dividend yield was considered in the option pricing model as a result of our new dividend program. The expected life (estimated period of time outstanding) of the stock options granted was estimated using the historical exercise behavior of employees.

        A summary of option activity for the three months ended March 31, 2010 is as follows:

        The following table provides the aggregate intrinsic value of stock options exercised and the aggregate fair value of stock options vested for the three months ended March 31, 2009 and 2010:

12

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

Restricted Stock

        Under our various stock option plans, we may also issue grants of restricted stock. We issued restricted stock in December 2007 and June 2009, which had a 5-year vesting period. The fair value of restricted stock is the excess of the market price of our common stock at the date of grant over the exercise price, which is zero. Included in our stock-based compensation expense for the three months ended March 31, 2009 and 2010 is a portion of the cost related to restricted stock granted in December 2007 and June 2009.

        A summary of restricted stock activity for the three months ended March 31, 2010 is as follows:

        No shares vested during the three months ended March 31, 2009 and 2010.

Employee Stock Purchase Plan

        We offer an employee stock purchase plan in which participation is available to substantially all U.S. and Canadian employees who meet certain service eligibility requirements (the "ESPP"). The ESPP provides a way for our eligible employees to become stockholders on favorable terms. The ESPP provides for the purchase of our common stock by eligible employees through successive offering periods. We generally have two 6-month offering periods per year, the first of which begins June 1 and ends November 30 and the second begins December 1 and ends May 31. During each offering period, participating employees accumulate after-tax payroll contributions, up to a maximum of 15% of their compensation, to pay the exercise price of their options. Participating employees may withdraw from an offering period before the purchase date and obtain a refund of the amounts withheld as payroll deductions. At the end of the offering period, outstanding options are exercised, and each employee's accumulated contributions are used to purchase our common stock. The price for shares purchased under the ESPP is 95% of the fair market price at the end of the offering period, without a look-back feature. As a result, we do not recognize compensation cost for our ESPP shares purchased. The ESPP was amended and approved by our stockholders on May 26, 2005 to increase the number of shares from 1,687,500 to 3,487,500. In the three months ended March 31, 2009 and 2010, there were no

13

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

offering periods which ended under the ESPP and no shares were issued. The number of shares available for purchase under the ESPP at March 31, 2010 was 811,701.

        As of March 31, 2010, unrecognized compensation cost related to the unvested portion of our Employee Stock-Based Awards was $55,614 and is expected to be recognized over a weighted-average period of 3.9 years.

        We generally issue shares for the exercises of stock options, issuance of restricted stock and issuance of shares under our ESPP from unissued reserved shares.

f.

Income Per Share—Basic and Diluted

        Basic net income per common share is calculated by dividing net income attributable to Iron Mountain Incorporated by the weighted average number of common shares outstanding. The calculation of diluted net income per share is consistent with that of basic net income per share but gives effect to all potential common shares (that is, securities such as options, warrants or convertible securities) that were outstanding during the period, unless the effect is antidilutive.

        The following table presents the calculation of basic and diluted net income per share attributable to Iron Mountain Incorporated:

g.

Revenues

        Our revenues consist of storage revenues as well as service revenues and are reflected net of sales and value added taxes. Storage revenues, both physical and digital, which are considered a key performance indicator for the information management services industry, consist of largely recurring

14

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

periodic charges related to the storage of materials or data (generally on a per unit basis). Service revenues are comprised of charges for related core service activities and a wide array of complementary products and services. Included in core service revenues are: (1) the handling of records including the addition of new records, temporary removal of records from storage, refiling of removed records, destruction of records, and permanent withdrawals from storage; (2) courier operations, consisting primarily of the pickup and delivery of records upon customer request; (3) secure shredding of sensitive documents; and (4) other recurring services including maintenance and support contracts. Our complementary services revenues include special project work, data restoration projects, fulfillment services, consulting services and product sales (including software licenses, specially designed storage containers and related supplies). Our secure shredding revenues include the sale of recycled paper (included in complementary services), the price of which can fluctuate from period to period, adding to the volatility and reducing the predictability of that revenue stream.

        We recognize revenue when the following criteria are met: persuasive evidence of an arrangement exists, services have been rendered, the sales price is fixed or determinable, and collectability of the resulting receivable is reasonably assured. Storage and service revenues are recognized in the month the respective storage or service is provided and customers are generally billed on a monthly basis on contractually agreed-upon terms. Amounts related to future storage or prepaid service contracts, including maintenance and support contracts, for customers where storage fees or services are billed in advance are accounted for as deferred revenue and recognized ratably over the applicable storage or service period or when the service is performed. Revenue from the sales of products is recognized when shipped to the customer and title has passed to the customer. Sales of software licenses are recognized at the time of product delivery to our customer or reseller and maintenance and support agreements are recognized ratably over the term of the agreement. Software license sales and maintenance and support accounted for less than 1% of our annual 2009 and first quarter of 2010 consolidated revenues. Within our Worldwide Digital Business segment, in certain instances, we process and host data for customers. In these instances, the processing fees are deferred and recognized over the estimated service period.

h.

Allowance for Doubtful Accounts and Credit Memo Reserves

        We maintain an allowance for doubtful accounts and credit memos for estimated losses resulting from the potential inability of our customers to make required payments and disputes regarding billing and service issues. When calculating the allowance, we consider our past loss experience, current and prior trends in our aged receivables and credit memo activity, current economic conditions, and specific circumstances of individual receivable balances. If the financial condition of our customers were to significantly change, resulting in a significant improvement or impairment of their ability to make payments, an adjustment of the allowance may be required. We consider accounts receivable to be delinquent after such time as reasonable means of collection have been exhausted. We charge-off uncollectible balances as circumstances warrant, generally, no later than one year past due.

i.

Income Taxes

        Our effective tax rates for the three months ended March 31, 2009 and 2010 were 54.0% and 61.6%, respectively. The primary reconciling items between the statutory rate of 35% and our overall

15

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

effective tax rate are state income taxes (net of federal benefit) and differences in the rates of tax at which our foreign earnings are subject, including foreign exchange gains and losses in different jurisdictions with different tax rates. During the three months ended March 31, 2009 and 2010, foreign currency gains were recorded in higher tax jurisdictions associated with our marking-to-market of debt and derivative instruments while foreign currency losses were recorded in lower tax jurisdictions associated with our marking-to-market of intercompany loan positions, which contributed 13.1% to the 2009 tax rate and 19.8% to the 2010 tax rate. We provide for income taxes during interim periods based on our estimate of the effective tax rate for the year. Discrete items and changes in our estimate of the annual effective tax rate are recorded in the period they occur.

        Accounting for income taxes requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the tax and financial reporting basis of assets and liabilities and for loss and credit carryforwards. Valuation allowances are provided when recovery of deferred tax assets is not considered more likely than not.

        We have elected to recognize interest and penalties associated with uncertain tax positions as a component of the provision for income taxes in the accompanying consolidated statements of operations. We recorded $1,250 and $1,172 for gross interest and penalties for the three months ended March 31, 2009 and 2010, respectively. We had $12,874 and $14,046 accrued for the payment of interest and penalties as of December 31, 2009 and March 31, 2010, respectively.

j.

Fair Value Measurements

        Entities are permitted under GAAP to elect to measure many financial instruments and certain other items at either fair value or cost. We did not elect the fair value measurement option for any of our financial assets or liabilities.

        Our financial assets or liabilities are measured using inputs from the three levels of the fair value hierarchy. A financial asset or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The three levels are as follows:

        Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date.

        Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs).

        Level 3—Unobservable inputs that reflect our assumptions about the assumptions that market participants would use in pricing the asset or liability.

16

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

        The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of March 31, 2010:

        Disclosures are required in the financial statements for items measured at fair value on a non-recurring basis. We did not have any material items that are measured at fair value on a non-recurring basis for the three months ended March 31, 2010.

        k.     New Accounting Pronouncements

        Effective at the start of a reporting entity's first fiscal year beginning after November 15, 2009, or January 1, 2010, for a calendar year-end entity, the Financial Accounting Standards Board (the "FASB") Accounting Standards Codification™ (the "Codification") will require more information about transfers of financial assets, including securitization transactions, and transactions where entities have continuing exposure to the risks related to transferred financial assets. The Codification eliminates the concept of a "qualifying special-purpose entity," changes the requirements for derecognizing financial assets, and requires additional disclosures about an entity's involvement with variable interest entities and any significant changes in risk exposure due to that involvement. A reporting entity will be required to disclose how its involvement with a variable interest entity affects such reporting entity's financial statements. The adoption of these Codification updates did not have a material impact on our consolidated financial statements and results of operations.

        In October 2009, the FASB issued amended guidance on multiple-deliverable revenue arrangements and software revenue recognition. The multiple-deliverable revenue arrangements updates to the Codification apply to all deliverables in contractual arrangements in all industries in which a vendor will perform multiple revenue-generating activities. The change to the Codification

17

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

creates a selling price hierarchy that an entity must use as evidence of fair value in separately accounting for all deliverables on a relative-selling-price basis which qualify for separation. The selling price hierarchy includes: (1) vendor-specific objective evidence; (2) third-party evidence and (3) estimated selling price. Broadly speaking, this update to the Codification will result in the possibility for some entities to recognize revenue earlier and more closely align with the economics of certain revenue arrangements if the other criteria for separation (e.g. standalone value to the customer) are met. The software revenue recognition guidance was issued to address factors that entities should consider when determining whether the software and non-software components of a product function together to deliver the product's essential functionality. The software revenue recognition updates to the Codification will allow revenue arrangements in which software and non-software components deliver together a product's essential functionality to follow the multiple-deliverable revenue recognition criteria as opposed to the criteria applicable to software revenue recognition. Both updates are effective for fiscal years beginning on or after June 15, 2010 and apply prospectively to new or materially modified revenue arrangements after its effective date. Early adoption is permitted; however, we do not anticipate early adopting. We are currently evaluating the impact of these Codification updates to our consolidated financial statements and results of operations.

        In January 2010, the FASB issued amended guidance improving disclosures about fair value measurements to add new requirements for disclosures about transfers into and out of Levels 1 and 2 and separate disclosures about purchases, sales, issuances, and settlements relating to Level 3 measurements. The new guidance also clarifies existing fair value disclosures about the level of disaggregation and about inputs and valuation techniques used to measure fair value. The change in the Codification requires an entity, in determining the appropriate classes of assets and liabilities, to consider the nature and risks of the assets and liabilities as well as their placement in the fair value hierarchy (Level 1, 2 or 3). The Codification update is effective for the first reporting period, including interim periods, beginning after December 15, 2009, except for the requirement to provide the Level 3 activity of purchases, sales, issuances, and settlements on a gross basis, which will be effective for fiscal years beginning after December 15, 2010. In the period of initial adoption, entities will not be required to provide the amended disclosures for any previous periods presented for comparative purposes. However, those disclosures are required for periods ending after initial adoption. Early adoption is permitted for the requirement to provide the Level 3 activity of purchases, sales, issuances and settlements on a gross basis; however, we do not anticipate early adopting. We do not expect adoption to have a material impact on our consolidated financial statements and results of operations.

        l.      Use of Estimates

        The preparation of financial statements in conformity with GAAP requires us to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities at the date of the financial statements and for the period then ended. On an on-going basis, we evaluate the estimates used. We base our estimates on historical experience, actuarial estimates, current conditions and various other assumptions that we believe to be reasonable under the circumstances. These estimates form the basis for making judgments about the carrying values of assets and liabilities and are not readily apparent from other sources. Actual results may differ from these estimates.

18

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(2) Summary of Significant Accounting Policies (Continued)

        m.    Accumulated Other Comprehensive Items, Net

        Accumulated other comprehensive items, net consists of foreign currency translation adjustments as of December, 31, 2009 and March 31, 2010, respectively.

        n.     Other Expense (Income), Net

        Other expense (income), net consists of the following:

(3) Derivative Instruments and Hedging Activities

        Every derivative instrument is required to be recorded in the balance sheet as either an asset or a liability measured at its fair value. Periodically, we acquire derivative instruments that are intended to hedge either cash flows or values which are subject to foreign exchange or other market price risk, and not for trading purposes. We have formally documented our hedging relationships, including identification of the hedging instruments and the hedged items, as well as our risk management objectives and strategies for undertaking each hedge transaction. Given the recurring nature of our revenues and the long term nature of our asset base, we have the ability and the preference to use long-term, fixed interest rate debt to finance our business, thereby preserving our long term returns on invested capital. We target approximately 75% of our debt portfolio to be fixed with respect to interest rates. Occasionally, we will use interest rate swaps as a tool to maintain our targeted level of fixed rate debt. In addition, we will use borrowings in foreign currencies, either obtained in the U.S. or by our foreign subsidiaries, to naturally hedge foreign currency risk associated with our international investments. Sometimes we enter into currency swaps to temporarily hedge an overseas investment, such as a major acquisition, while we arrange permanent financing or to hedge our exposures due to foreign currency exchange movements related to our intercompany accounts with and between our foreign subsidiaries. As of December 31, 2009 and March 31, 2010, none of our derivative instruments contained credit-risk related contingent features.

        We have entered into a number of forward contracts to hedge our exposures in British pounds sterling. As of March 31, 2010, we had an outstanding forward contract to purchase 110,164 U.S. dollars and sell 73,600 British pounds sterling to hedge our intercompany exposures with IME. At the maturity of the forward contracts we may enter into new forward contracts to hedge movements in the underlying currencies. At the time of settlement, we either pay or receive the net settlement amount from the forward contract and recognize this amount in other (income) expense, net in the accompanying statement of operations as a realized foreign exchange gain or loss. We have not designated these forward contracts as hedges. During the three months ended March 31, 2009 and

19

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(3) Derivative Instruments and Hedging Activities (Continued)

2010, there was $15,022 and $10,952 in net cash receipts, respectively, included in cash from operating activities related to settlements associated with these foreign currency forward contracts. The following table provides the fair value of our derivative instruments as of December 31, 2009 and March 31, 2010 and their gains and losses for the three months ended March 31, 2009 and 2010:

        In the third quarter of 2007, we designated a portion of our 6³/4% Euro Senior Subordinated Notes due 2018 issued by IMI as a hedge of net investment of certain of our Euro denominated subsidiaries. For the three months ended March 31, 2009 and 2010, we designated 135,000 and 81,000 Euros, respectively, of our 6³/4% Euro Senior Subordinated Notes due 2018 issued by IMI as a hedge of net investment of certain of our Euro denominated subsidiaries. As a result, we recorded $12,001 ($7,321, net of tax) of foreign exchange gains for the three months ended March 31, 2009 and $6,861 ($4,288, net of tax) of foreign exchange gains for the three months ended March 31, 2010 related to the change in fair value of such debt due to currency translation adjustments which is a component of accumulated

20

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(3) Derivative Instruments and Hedging Activities (Continued)

other comprehensive items, net included in equity. As of March 31, 2010, net gains of $7,647 are recorded in accumulated other comprehensive items, net associated with this net investment hedge.

(4) Acquisitions

        We account for acquisitions using the purchase method of accounting, and accordingly, the results of operations for each acquisition have been included in our consolidated results from their respective acquisition dates. Cash consideration for our various acquisitions was primarily provided through borrowings under our credit facilities and cash equivalents on-hand. The unaudited pro forma results of operations for the period ended March 31, 2010 are not presented due to the insignificant impact of the 2010 acquisitions on our consolidated results of operations.

        In February 2010, we acquired 100% of Mimosa Systems, Inc. ("Mimosa"), a leader in enterprise-class digital content archiving solutions, for approximately $112,000 in cash and approximately $2,700 in fair value of options issued. Mimosa, based in Santa Clara, California, provides an on-premises integrated archive for email, SharePoint data and files, and complements IMI's existing enterprise-class, cloud-based digital archive services. NearPoint, Mimosa's enterprise archiving platform, has applications for retention and disposition, eDiscovery, compliance supervision, classification, recovery, and end-user search, enabling customers to reduce risk and lower their eDiscovery and storage costs. Goodwill associated with the Mimosa acquisition was allocated to the Worldwide Digital Business (excluding Stratify) reporting unit. We deposited $11,200 of the cash consideration payable in our acquisition of Mimosa into escrow to secure certain indemnification obligations of the former stockholders of Mimosa (the "Mimosa Stockholders") and to satisfy certain other obligations of the Mimosa Stockholders. On the 15-month anniversary of the closing of the acquisition, or May 16, 2011, amounts remaining in the escrow fund will be distributed to the Mimosa Stockholders, minus (i) $750 which shall continue to be held as security for certain types of claims and (ii) any amounts held for unresolved indemnification claims made by us. On the 24-month anniversary of the closing, or February 16, 2012, the balance of the escrow fund less any amounts held for unresolved claims will be distributed to the Mimosa Stockholders. The allocation of the purchase price will be finalized upon the final settlement of the purchase price with the Mimosa Stockholders and the subsequent completion of the analyses of the fair value of Mimosa's assets and liabilities and certain tax matters. The analyses include examination of the underlying books and tax records, completion of an appraisal of certain intangible assets and liabilities and a full assessment of legal and tax contingencies.

21

Table of Contents

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(In Thousands, Except Share and Per Share Data)

(Unaudited)

(4) Acquisitions (Continued)

        A summary of the consideration paid for acquisitions in 2010 and the allocation of the purchase price of the acquisitions is as follows: