Iron Mountain Incorporated
US ˙ NYSE ˙ US46284V1017

SecurityIRM / Iron Mountain Incorporated
InstitutionWoodstock Corp
Latest Disclosed Ownership65,497 shares
Latest Disclosed Value $ 6,689,864
Woodstock Corp reports 2.79% increase in ownership of IRM / Iron Mountain Incorporated

On April 8, 2026 - Woodstock Corp filed a 13F-HR form disclosing ownership of 65,497 shares of Iron Mountain Incorporated (US:IRM) valued at $6,689,864 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 14, 2026 disclosing 63,717 shares of Iron Mountain Incorporated. This represents a change in shares of 2.79% during the quarter. The current value of the position is $8,380,341 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)
2026-04-08 2026-03-31 13F Iron Mountain COMMON STOCK 46284V101 65,497 1,780 2.79 6,690 26.57 0.5955
2026-01-14 2025-12-31 13F Iron Mountain COMMON STOCK 46284V101 63,717 660 1.05 5,285 -17.78 0.4536
2025-10-07 2025-09-30 13F Iron Mountain COMMON STOCK 46284V101 63,057 7,679 13.87 6,428 13.17 0.5570
2025-07-09 2025-06-30 13F Iron Mountain COMMON STOCK 46284V101 55,378 1,950 3.65 5,680 23.59 0.5220
2025-04-09 2025-03-31 13F Iron Mountain COMMON STOCK 46284V101 53,428 -11,218 -17.35 4,597 -32.35 0.4541
2025-01-15 2024-12-31 13F Iron Mountain COMMON STOCK 46284V101 64,646 -2,900 -4.29 6,795 -15.35 0.6546
2024-10-11 2024-09-30 13F Iron Mountain COMMON STOCK 46284V101 67,546 -4,235 -5.90 8,026 24.76 0.7723
2024-07-08 2024-06-30 13F Iron Mountain COMMON STOCK 46284V101 71,781 -560 -0.77 6,433 10.88 0.6541
2024-04-09 2024-03-31 13F Iron Mountain COMMON STOCK 46284V101 72,341 -2,993 -3.97 5,802 10.07 0.6007
2024-01-08 2023-12-31 13F Iron Mountain COMMON STOCK 46284V101 75,334 -1,030 -1.35 5,272 16.13 0.6105
2023-10-10 2023-09-30 13F Iron Mountain COMMON STOCK 46284V101 76,364 -425 -0.55 4,540 4.03 0.5693
2023-07-07 2023-06-30 13F Iron Mountain COMMON STOCK 46284V101 76,789 -370 -0.48 4,363 6.88 0.5148
2023-04-06 2023-03-31 13F Iron Mountain COMMON STOCK 46284V101 77,159 0 0.00 4,082 6.14 0.5206
2023-01-10 2022-12-31 13F Iron Mountain COMMON STOCK 46284V101 77,159 -1,502 -1.91 3,846 11.19 0.5112
2022-10-11 2022-09-30 13F Iron Mountain COMMON STOCK 46284V101 78,661 -7,200 -8.39 3,459 -17.27 0.5146
2022-07-11 2022-06-30 13F Iron Mountain COMMON STOCK 46284V101 85,861 -60 -0.07 4,181 -12.18 0.5803
2022-04-07 2022-03-31 13F Iron Mountain COMMON STOCK 46284V101 85,921 -23,898 -21.76 4,761 -17.16 0.5575
2022-01-07 2021-12-31 13F Iron Mountain COMMON STOCK 46284V101 109,819 -2,000 -1.79 5,747 18.28 0.6018
2021-10-05 2021-09-30 13F Iron Mountain COMMON STOCK 46284V101 111,819 -727 -0.65 4,859 2.02 0.5666
2021-07-06 2021-06-30 13F Iron Mountain COMMON STOCK 46284V101 112,546 -3,700 -3.18 4,763 10.72 0.5604
2021-04-05 2021-03-31 13F Iron Mountain COMMON STOCK 46284V101 116,246 2,050 1.80 4,302 27.81 0.5469
2021-01-06 2020-12-31 13F Iron Mountain COMMON STOCK 46284V101 114,196 5,590 5.15 3,366 15.67 0.4505
2020-10-02 2020-09-30 13F Iron Mountain COMMON STOCK 46284V101 108,606 13,085 13.70 2,910 16.73 0.4699
2020-07-07 2020-06-30 13F Iron Mountain COMMON STOCK 46284V101 95,521 40,337 73.10 2,493 89.87 0.4250
2020-04-03 2020-03-31 13F Iron Mountain COMMON STOCK 46284V101 55,184 6,325 12.95 1,313 -15.67 0.2675
2020-01-13 2019-12-31 13F Iron Mountain COMMON STOCK 46284V101 48,859 19,102 64.19 1,557 61.51 0.2536
2019-10-02 2019-09-30 13F Iron Mountain COMMON STOCK 46284V101 29,757 1,750 6.25 964 9.92 0.1680
2019-07-03 2019-06-30 13F Iron Mountain COMMON STOCK 46284V101 28,007 2,150 8.31 877 -4.36 0.1531
2019-04-05 2019-03-31 13F Iron Mountain COMMON STOCK 46284V101 25,857 1,209 4.91 917 14.77 0.1643
2019-01-08 2018-12-31 13F Iron Mountain COMMON STOCK 46284V101 24,648 -6,750 -21.50 799 -26.29 0.1603
2018-10-03 2018-09-30 13F Iron Mountain COMMON STOCK 46284V101 31,398 2,900 10.18 1,084 8.62 0.1832
2018-07-23 2018-06-30 13F Iron Mountain COMMON STOCK 46284V101 28,498 1,000 3.64 998 10.40 0.1837
2018-04-19 2018-03-31 13F Iron Mountain COMMON STOCK 46284V101 27,498 2,350 9.34 904 -4.74 0.1709
2018-01-24 2017-12-31 13F Iron Mountain COMMON STOCK 46284V101 25,148 8,236 48.70 949 44.22 0.1750
2017-10-06 2017-09-30 13F Iron Mountain COMMON STOCK 46284V101 16,912 300 1.81 658 15.24 0.1254
2017-07-13 2017-06-30 13F Iron Mountain COMMON STOCK 46284V101 16,612 5,500 49.50 571 44.19 0.1119
2017-04-05 2017-03-31 13F Iron Mountain COMMON STOCK 46284V101 11,112 2,250 25.39 396 37.50 0.0798
2017-01-05 2016-12-31 13F Iron Mountain COMMON STOCK 46284V101 8,862 0 0.00 288 -13.51 0.0584
2016-10-06 2016-09-30 13F Iron Mountain Inc Reit OTHER 46284V101 8,862 1,400 18.76 333 12.12 0.0681
2016-08-03 2016-06-30 13F Iron Mountain Inc Reit COMMON STOCK 46284V101 7,462 0 0.00 297 17.39 0.0613
2016-05-10 2016-03-31 13F Iron Mountain Inc Reit COMMON STOCK 46284V101 7,462 -778 -9.44 253 13.45 0.0532
2016-01-11 2015-12-31 13F IRON MOUNTAIN INC REIT COMMON STOCK 46284V101 8,240 200 2.49 223 -10.44 0.0490
2015-10-16 2015-09-30 13F IRON MOUNTAIN INC REIT COMMON STOCK 46284V101 8,040 -3,217 -28.58 249 -28.65 0.0567
2015-07-07 2015-06-30 13F IRON MOUNTAIN INC REIT COMMON STOCK 46284V101 11,257 -166 -1.45 349 -16.31 0.0658
2015-04-09 2015-03-31 13F IRON MOUNTAIN INC REIT COMMON STOCK 46284V101 11,423 0 0.00 417 -5.66 0.0774
2015-02-13 2014-12-31 13F IRON MTN INC PA REIT COMMON STOCK 462846106 11,423 857 8.11 442 28.12 0.0821
2014-10-06 2014-09-30 13F IRON MTN INC PA REIT COMMON STOCK 462846106 10,566 0 0.00 345 -8.00 0.0664
2014-07-07 2014-06-30 13F IRON MTN INC PA COMMON STOCK 462846106 10,566 1,600 17.85 375 51.82 0.0664
2014-04-07 2014-03-31 13F IRON MTN INC PA COMMON STOCK 462846106 8,966 -4,272 -32.27 247 -31.01 0.0459
2013-10-07 2013-09-30 13F IRON MTN INC PA COMMON STOCK 462846106 13,238 -4,207 -24.12 358 -22.84 0.0709
2013-07-09 2013-06-30 13F IRON MTN INC PA COMMON STOCK 462846106 17,445 17,445 464 0.0948
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.