Iron Mountain Incorporated
US ˙ NYSE ˙ US46284V1017

SecurityIRM / Iron Mountain Incorporated
InstitutionWhittier Trust Co
Latest Disclosed Ownership1,497 shares
Latest Disclosed Value $ 156,227
Whittier Trust Co reports 14.01% decrease in ownership of IRM / Iron Mountain Incorporated

On April 28, 2026 - Whittier Trust Co filed a 13F-HR form disclosing ownership of 1,497 shares of Iron Mountain Incorporated (US:IRM) valued at $152,904 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 1,741 shares of Iron Mountain Incorporated. This represents a change in shares of -14.01% during the quarter. The current value of the position is $191,541 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-04-28 2026-03-31 13F IRON MTN common 46284V101 1,497 -244 -14.01 156 6.12 0.0009
2026-01-26 2025-12-31 13F IRON MTN common 46284V101 1,741 -156 -8.22 148 -25.76 0.0016
2025-10-31 2025-09-30 13F IRON MTN INC DEL common 46284V101 1,897 -923 -32.73 199 -31.49 0.0023
2025-07-30 2025-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 2,820 -445 -13.63 289 3.21 0.0035
2025-05-02 2025-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 3,265 108 3.42 281 -15.41 0.0039
2025-02-11 2024-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 3,157 144 4.78 332 -7.54 0.0044
2024-10-21 2024-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 3,013 -1,864 -38.22 358 -18.08 0.0048
2024-07-29 2024-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 4,877 1,899 63.77 437 83.61 0.0062
2024-05-02 2024-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 2,978 0 0.00 239 14.42 0.0035
2024-01-11 2023-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 2,978 -250 -7.74 208 8.90 0.0034
2023-10-27 2023-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 3,228 47 1.48 192 6.11 0.0034
2023-07-24 2023-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 3,181 0 0.00 181 7.14 0.0031
2023-04-21 2023-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 3,181 258 8.83 168 15.86 0.0031
2023-01-25 2022-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 2,923 220 8.14 146 21.85 0.0028
2022-10-21 2022-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 2,703 0 0.00 119 -9.85 0.0025
2022-07-28 2022-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 2,703 1,750 183.63 132 149.06 0.0027
2022-04-29 2022-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 953 -2,100 -68.78 53 -66.87 0.0009
2022-01-19 2021-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 3,053 2,100 220.36 160 290.24 0.0026
2021-11-01 2021-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 953 0 0.00 41 2.50 0.0007
2021-07-29 2021-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 953 0 0.00 40 14.29 0.0007
2021-04-26 2021-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 953 0 0.00 35 25.00 0.0007
2021-01-29 2020-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 953 0 0.00 28 7.69 0.0006
2020-10-30 2020-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 953 525 122.66 26 136.36 0.0006
2020-07-10 2020-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 11 10.00 0.0003
2020-04-27 2020-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 10 -28.57 0.0003
2020-01-31 2019-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 14 0.00 0.0004
2019-10-18 2019-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 14 7.69 0.0004
2019-07-23 2019-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 13 -13.33 0.0004
2019-04-29 2019-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 15 7.14 0.0005
2019-02-07 2018-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 14 -6.67 0.0005
2018-10-23 2018-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 15 0.00 0.0005
2018-07-27 2018-06-30 13F/A-1 IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 15 7.14 0.0005
2018-07-20 2018-06-30 13F IRON MTN INC COM US SMALL AND MID-CAP EQUITIES 462846106 775 347 27
2018-05-01 2018-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 14 -12.50 0.0005
2018-02-07 2017-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 428 0 0.00 16 -5.88 0.0006
2017-10-23 2017-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 428 -768 -64.21 17 -58.54 0.0006
2017-07-20 2017-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 1,196 0 0.00 41 -2.38 0.0016
2017-04-26 2017-03-31 13F IRON MTN INC REIT'S 46284V101 1,196 0 0.00 42 7.69 0.0017
2017-01-18 2016-12-31 13F IRON MTN INC NEW COM REIT'S 46284V101 1,196 0 0.00 39 -13.33 0.0017
2016-11-10 2016-09-30 13F IRON MTN INC NEW COM REIT'S 46284V101 1,196 0 0.00 45 -6.25 0.0020
2016-07-28 2016-06-30 13F IRON MTN INC NEW COM REIT'S 46284V101 1,196 0 0.00 48 17.07 0.0021
2016-04-28 2016-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 1,196 -326 -21.42 41 0.00 0.0018
2016-02-10 2015-12-31 13F IRON MTN INC NEW COM REIT?S 46284V101 1,522 -2,481 -61.98 41 -66.94 0.0019
2015-11-12 2015-09-30 13F IRON MTN INC NEW COM REIT?S 46284V101 4,003 326 8.87 124 8.77 0.0060
2015-08-13 2015-06-30 13F IRON MTN INC NEW COM REIT?S 46284V101 3,677 428 13.17 114 -3.39 0.0051
2015-05-05 2015-03-31 13F IRON MTN INC NEW COM REIT'S 46284V101 3,249 3,249 118 0.0054
2015-02-04 2014-12-31 13F IRON MTN INC COM US SMALL AND MID-CAP EQUITIES 462846106 0 -1,004 -100.00 0 -100.00
2014-11-07 2014-09-30 13F IRON MTN INC COM US SMALL AND MID-CAP EQUITIES 462846106 1,004 229 29.55 33 22.22 0.0016
2014-08-04 2014-06-30 13F IRON MTN INC COM US SMALL AND MID-CAP EQUITIES 462846106 775 0 0.00 27 28.57 0.0013
2014-05-01 2014-03-31 13F IRON MTN INC COM US SMALL AND MID-CAP EQUITIES 462846106 775 0 0.00 21 -12.50 0.0011
2014-02-05 2013-12-31 13F IRON MTN INC COM US SMALL AND MID-CAP EQUITIES 462846106 775 0 0.00 24 14.29 0.0012
2013-11-18 2013-09-30 13F IRON MTN COM 462846106 775 100 14.81 21 16.67 0.0011
2013-08-14 2013-06-30 13F IRON MTN COM 462846106 675 675 18 0.0010
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.