Iron Mountain Incorporated
US ˙ NYSE ˙ US46284V1017

SecurityIRM / Iron Mountain Incorporated
InstitutionAmalgamated Bank
Latest Disclosed Ownership53,267 shares
Latest Disclosed Value $ 5,441
Amalgamated Bank reports 3.12% decrease in ownership of IRM / Iron Mountain Incorporated

On May 8, 2026 - Amalgamated Bank filed a 13F-HR form disclosing ownership of 53,267 shares of Iron Mountain Incorporated (US:IRM) valued at $5,440,691 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 54,985 shares of Iron Mountain Incorporated. This represents a change in shares of -3.12% during the quarter. The current value of the position is $6,815,513 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)
2026-05-08 2026-03-31 13F IRON MOUNTAIN COM 46284V101 53,267 -1,718 -3.12 5 25.00 0.0416
2026-02-05 2025-12-31 13F IRON MOUNTAIN COM 46284V101 54,985 -1,113 -1.98 5 -20.00 0.0329
2025-10-29 2025-09-30 13F IRON MOUNTAIN COM 46284V101 56,098 -973 -1.70 6 0.00 0.0409
2025-08-04 2025-06-30 13F IRON MOUNTAIN COM 46284V101 57,071 -3,014 -5.02 6 0.00 0.0452
2025-04-25 2025-03-31 13F IRON MOUNTAIN COM 46284V101 60,085 1,571 2.68 5 -16.67 0.0442
2025-02-04 2024-12-31 13F IRON MOUNTAIN COM 46284V101 58,514 -1,341 -2.24 6 -14.29 0.0505
2024-10-30 2024-09-30 13F IRON MOUNTAIN COM 46284V101 59,855 -1,582 -2.57 7 40.00 0.0586
2024-08-12 2024-06-30 13F IRON MOUNTAIN COM 46284V101 61,437 -163 -0.26 6 25.00 0.0469
2024-04-23 2024-03-31 13F IRON MOUNTAIN COM 46284V101 61,600 -17,393 -22.02 5 -20.00 0.0423
2024-02-06 2023-12-31 13F IRON MOUNTAIN COM 46284V101 78,993 -3,217 -3.91 6 25.00 0.0441
2023-11-08 2023-09-30 13F IRON MOUNTAIN COM 46284V101 82,210 7,776 10.45 5 0.00 0.0416
2023-08-11 2023-06-30 13F IRON MOUNTAIN COM 46284V101 74,434 -27,391 -26.90 4 -20.00 0.0342
2023-05-02 2023-03-31 13F IRON MOUNTAIN COM 46284V101 101,825 -7,298 -6.69 5 0.00 0.0459
2023-02-10 2022-12-31 13F IRON MOUNTAIN COM 46284V101 109,123 1,960 1.83 5 -99.89 0.0485
2022-11-09 2022-09-30 13F IRON MOUNTAIN COM 46284V101 107,163 -6,139 -5.42 4,712 -14.59 0.0455
2022-08-15 2022-06-30 13F IRON MOUNTAIN COM 46284V101 113,302 7,603 7.19 5,517 -5.81 0.0514
2022-08-25 2022-03-31 13F/A-1 IRON MOUNTAIN COM 46284V101 105,699 -146 -0.14 5,857 5.74 0.0455
2022-06-30 2022-03-31 13F IRON MOUNTAIN COM 46284V101 105,699 -146 5,857 0.0465
2022-02-15 2021-12-31 13F/A-1 IRON MOUNTAIN COM 46284V101 105,845 -8,623 -7.53 5,539 11.36 0.0409
2022-02-15 2021-12-31 13F IRON MOUNTAIN COM 46284V101 105,845 -8,623 5,539 0.0409
2021-10-29 2021-09-30 13F IRON MOUNTAIN COM 46284V101 114,468 -3,066 -2.61 4,974 0.00 0.0420
2021-08-16 2021-06-30 13F IRON MOUNTAIN COM 46284V101 117,534 69,071 142.52 4,974 177.26 0.0399
2021-05-13 2021-03-31 13F IRON MOUNTAIN COM 46284V101 48,463 -3,677 -7.05 1,794 16.72 0.0673
2021-02-12 2020-12-31 13F IRON MOUNTAIN COM 46284V101 52,140 57 0.11 1,537 10.18 0.0582
2020-10-30 2020-09-30 13F IRON MOUNTAIN COM 46284V101 52,083 -1,116 -2.10 1,395 0.50 0.0606
2020-08-10 2020-06-30 13F IRON MOUNTAIN COM 46284V101 53,199 -13,816 -20.62 1,388 -12.98 0.0642
2020-05-13 2020-03-31 13F IRON MOUNTAIN COM 46284V101 67,015 -1,348 -1.97 1,595 -26.80 0.0390
2020-02-13 2019-12-31 13F IRON MOUNTAIN COM 46284V101 68,363 6,312 10.17 2,179 8.41 0.0401
2019-11-13 2019-09-30 13F IRON MOUNTAIN COM 46284V101 62,051 449 0.73 2,010 4.25 0.0423
2019-08-14 2019-06-30 13F IRON MOUNTAIN COM 46284V101 61,602 3,319 5.69 1,928 -6.72 0.0450
2019-05-15 2019-03-31 13F IRON MOUNTAIN COM 46284V101 58,283 1,161 2.03 2,067 11.67 0.0501
2019-02-15 2018-12-31 13F IRON MOUNTAIN COM 46284V101 57,122 -255 -0.44 1,851 -6.56 0.0524
2018-11-14 2018-09-30 13F IRON MOUNTAIN COM 46284V101 57,377 -865 -1.49 1,981 -2.84 0.0490
2018-07-18 2018-06-30 13F IRON MOUNTAIN COM 46284V101 58,242 -5,409 -8.50 2,039 -2.53 0.0498
2018-05-22 2018-03-31 13F IRON MOUNTAIN COM 46284V101 63,651 4,355 7.34 2,092 -6.48 0.0555
2018-02-13 2017-12-31 13F IRON MOUNTAIN COM 46284V101 59,296 5,700 10.64 2,237 7.29 0.0605
2017-11-09 2017-09-30 13F IRON MOUNTAIN COM 46284V101 53,596 728 1.38 2,085 14.75 0.0649
2017-08-10 2017-06-30 13F IRON MOUNTAIN COM 46284V101 52,868 10,953 26.13 1,817 21.54 0.0596
2017-05-12 2017-03-31 13F IRON MOUNTAIN COM 46284V101 41,915 -8,534 -16.92 1,495 -8.79 0.0744
2017-02-14 2016-12-31 13F IRON MOUNTAIN COM 46284V101 50,449 4,812 10.54 1,639 -4.32 0.0741
2016-11-15 2016-09-30 13F/A-1 IRON MOUNTAIN COM 46284V101 45,637 92 0.20 1,713 1.54 0.0994
2016-11-14 2016-09-30 13F IRON MOUNTAIN COM 46284V101 6,792 255
2016-08-16 2016-06-30 13F IRON MOUNTAIN COM 46284V101 45,545 19,618 75.67 1,687 91.92 0.0976
2016-05-11 2016-03-31 13F IRON MOUNTAIN COM 46284V101 25,927 2,082 8.73 879 36.49 0.0856
2016-02-10 2015-12-31 13F IRON MOUNTAIN COM 46284V101 23,845 -1,597 -6.28 644 -18.38 0.0794
2015-11-04 2015-09-30 13F IRON MOUNTAIN COM 46284V101 25,442 435 1.74 789 1.81 0.0828
2015-07-10 2015-06-30 13F IRON MOUNTAIN COM 46284V101 25,007 4,648 22.83 775 4.31 0.0761
2015-04-22 2015-03-31 13F IRON MOUNTAIN COM 46284V101 20,359 20,359 743 0.0907
2015-01-29 2014-12-31 13F IRON MTN INC PA COM 462846106 0 -18,213 -100.00 0 -100.00
2014-11-14 2014-09-30 13F IRON MTN INC PA COM 462846106 18,213 223 1.24 595 -6.74 0.0885
2014-08-11 2014-06-30 13F IRON MTN INC PA COM 462846106 17,990 17,990 638 0.0963
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.