Iron Mountain Incorporated
US ˙ NYSE ˙ US46284V1017

SecurityIRM / Iron Mountain Incorporated
InstitutionMacquarie Group Ltd
Latest Disclosed Ownership270,616 shares
Latest Disclosed Value $ 27,640,719
Macquarie Group Ltd reports 7.64% decrease in ownership of IRM / Iron Mountain Incorporated

On May 15, 2026 - Macquarie Group Ltd filed a 13F-HR form disclosing ownership of 270,616 shares of Iron Mountain Incorporated (US:IRM) valued at $27,640,718 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 292,992 shares of Iron Mountain Incorporated. This represents a change in shares of -7.64% during the quarter. The current value of the position is $35,247,734 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)
2026-05-15 2026-03-31 13F IRON MTN INC DEL COM 46284V101 270,616 -22,376 -7.64 27,641 13.73 0.1287
2026-02-13 2025-12-31 13F IRON MTN INC DEL COM 46284V101 292,992 6,408 2.24 24,304 -16.81 0.1062
2025-11-13 2025-09-30 13F IRON MTN INC DEL COM 46284V101 286,584 -2,400 -0.83 29,214 -1.44 0.0341
2025-08-14 2025-06-30 13F IRON MTN INC DEL COM 46284V101 288,984 5,728 2.02 29,641 21.63 0.0364
2025-08-14 2025-03-31 13F/A-1 IRON MTN INC DEL COM 46284V101 283,256 24,284 9.38 24,371 -6.34 0.0303
2025-05-15 2025-03-31 13F IRON MTN INC DEL COM 46284V101 283,256 24,284 22,946 0.0187
2025-02-14 2024-12-31 13F IRON MTN INC DEL COM 46284V101 258,972 -26,097 -9.15 26,022 -23.19 0.0316
2024-11-14 2024-09-30 13F IRON MTN INC DEL COM 46284V101 285,069 -15,689 -5.22 33,875 25.68 0.0366
2024-08-09 2024-06-30 13F IRON MTN INC DEL COM 46284V101 300,758 125,080 71.20 26,954 91.35 0.0309
2024-05-14 2024-03-31 13F IRON MTN INC DEL COM 46284V101 175,678 5,098 2.99 14,087 18.00 0.0160
2024-02-14 2023-12-31 13F IRON MTN INC DEL COM 46284V101 170,580 85,763 101.12 11,937 136.75 0.0138
2023-11-14 2023-09-30 13F IRON MTN INC DEL COM 46284V101 84,817 44,465 110.19 5,043 119.98 0.0063
2023-10-27 2023-06-30 13F/A-2 IRON MTN INC DEL COM 46284V101 40,352 -2,571 -5.99 2,292 0.97 0.0026
2023-10-12 2023-06-30 13F/A-1 IRON MTN INC DEL COM 46284V101 40,352 -2,571 2,292 0.0023
2023-08-14 2023-06-30 13F IRON MTN INC DEL COM 46284V101 40,352 -2,571 2,292 0.0023
2023-06-01 2023-03-31 13F/A-1 IRON MTN INC DEL COM 46284V101 42,923 -53,913 -55.67 2,271 -52.97 0.0027
2023-05-15 2023-03-31 13F IRON MTN INC DEL COM 46284V101 42,923 -53,913 2,271 0.0021
2023-02-21 2022-12-31 13F IRON MTN INC DEL COM 46284V101 96,836 8,702 9.87 4,827 24.57 0.0057
2022-11-14 2022-09-30 13F IRON MTN INC DEL COM 46284V101 88,134 3,590 4.25 3,875 -5.88 0.0048
2022-08-17 2022-06-30 13F/A-1 IRON MTN INC COM 46284V101 84,544 1,677 2.02 4,117 -10.32 0.0046
2022-08-15 2022-06-30 13F IRON MTN INC COM 46284V101 84,544 1,677 4,117 0.0015
2022-05-16 2022-03-31 13F IRON MTN INC COM 46284V101 82,867 -9,886 -10.66 4,591 -5.42 0.0035
2022-02-11 2021-12-31 13F IRON MTN INC COM 46284V101 92,753 -47,433 -33.84 4,854 -20.32 0.0040
2021-11-12 2021-09-30 13F IRON MTN INC COM 46284V101 140,186 2,694 1.96 6,092 4.69 0.0052
2021-08-13 2021-06-30 13F IRON MTN INC COM 46284V101 137,492 6,720 5.14 5,819 20.23 0.0048
2021-05-14 2021-03-31 13F IRON MTN INC COM 46284V101 130,772 40,550 44.94 4,840 81.95 0.0068
2021-02-16 2020-12-31 13F IRON MTN INC COM 46284V101 90,222 82,596 1,083.08 2,660 1,203.92 0.0039
2020-11-13 2020-09-30 13F IRON MTN INC COM 46284V101 7,626 4,126 117.89 204 124.18 0.0003
2020-08-11 2020-06-30 13F IRON MTN INC COM 46284V101 3,500 0 0.00 91 9.64 0.0002
2020-05-15 2020-03-31 13F IRON MTN INC COM 46284V101 3,500 0 0.00 83 -25.89 0.0002
2020-03-18 2019-12-31 13F/A-2 IRON MTN INC COM 46284V101 3,500 -300 -7.89 112 -8.94 0.0002
2020-02-28 2019-12-31 13F/A-1 IRON MTN INC COM 46284V101 3,500 0 112 0.0002
2020-02-14 2019-12-31 13F IRON MTN INC COM 46284V101 3,500 -300 112 140.5505
2019-11-14 2019-09-30 13F IRON MTN INC COM 46284V101 3,800 0 0.00 123 3.36 0.0002
2019-11-06 2019-06-30 13F/A-2 IRON MTN INC COM 46284V101 3,800 0 0.00 119 -11.85 0.0002
2019-09-24 2019-06-30 13F/A-1 IRON MTN INC COM 46284V101 3,800 0 119 0.0002
2019-08-14 2019-06-30 13F IRON MTN INC COM 46284V101 3,800 0 119
2019-05-15 2019-03-31 13F IRON MTN INC COM 46284V101 3,800 0 0.00 135 9.76 0.0002
2019-02-15 2018-12-31 13F IRON MTN INC COM 46284V101 3,800 -400 -9.52 123 -15.17 0.0002
2018-11-15 2018-09-30 13F IRON MTN INC COM 46284V101 4,200 0 0.00 145 -1.36 0.0002
2019-03-21 2018-06-30 13F/A-1 IRON MTN INC COM 46284V101 4,200 0 0.00 147 6.52 0.0003
2018-08-14 2018-06-30 13F JACOBS ENGR GROUP INC DEL COM 46284V101 4,200 0 147
2018-05-11 2018-03-31 13F IRON MTN INC COM 46284V101 4,200 -25,737 -85.97 138 -89.35 0.0003
2018-02-14 2017-12-31 13F IRON MTN INC COM 46284V101 29,937 14,539 94.42 1,296 116.36 0.0023
2017-11-08 2017-09-30 13F IRON MTN INC COM 46284V101 15,398 -29,568 -65.76 599 -61.23 0.0011
2017-08-14 2017-06-30 13F IRON MTN INC COM 46284V101 44,966 -12,858 -22.24 1,545 -25.11 0.0028
2017-05-15 2017-03-31 13F Iron Mountain COM 46284V101 57,824 -102,914 -64.03 2,063 -60.48 0.0037
2017-03-30 2016-12-31 13F/A-1 Iron Mountain REIT 46284V101 160,738 116,715 265.12 5,220 215.79 0.0100
2017-02-15 2016-12-31 13F Iron Mountain COMMON 46284V101 160,738 5,220
2016-11-15 2016-09-30 13F Iron Mountain COMMON 46284V101 44,023 -353,185 -88.92 1,653 -89.55 0.0032
2016-09-14 2016-06-30 13F/A-1 Iron Mountain common stock 46284V101 397,208 393,294 10,048.39 15,821 11,795.49 0.0311
2016-08-15 2016-06-30 13F Iron Mountain Common Stock 46284V101 786,418 31,323
2016-05-16 2016-03-31 13F Iron Mountain REIT 46284V101 3,914 0 0.00 133 25.47 0.0003
2016-02-16 2015-12-31 13F Iron Mountain REIT 46284V101 3,914 -7,000 -64.14 106 -68.73 0.0002
2015-11-16 2015-09-30 13F Iron Mountain REIT 46284V101 10,914 0 0.00 339 0.30 0.0007
2015-08-21 2015-06-30 13F/A-1 Iron Mountain REIT 46284V101 10,914 0 0.00 338 -15.08 0.0007
2015-08-14 2015-06-30 13F Iron Mountain REIT 46284V101 10,914 338
2015-05-18 2015-03-31 13F Iron Mountain REIT 46284V101 10,914 10,914 398 0.0008
2015-02-17 2014-12-31 13F Iron Mountain REIT 462846106 0 -12,976 -100.00 0 -100.00
2014-11-14 2014-09-30 13F Iron Mountain REIT 462846106 12,976 0 0.00 424 -7.83 0.0009
2014-08-14 2014-06-30 13F Iron Mountain Common 462846106 12,976 -500 -3.71 460 23.66 0.0010
2014-05-15 2014-03-31 13F Iron Mountain Common Stock 462846106 13,476 10,100 299.17 372 264.71 0.0006
2014-02-14 2013-12-31 13F Iron Mountain Common Stock 462846106 3,376 2,288 210.29 102 251.72 0.0002
2013-11-14 2013-09-30 13F Iron Mountain Common Stock 462846106 1,088 0 0.00 29 0.00 0.0001
2013-08-16 2013-06-30 13F/A-1 Iron Mountain Common Stock 462846106 1,088 1,088 29 0.0001
2013-08-14 2013-06-30 13F Iron Mountain Common Stock 462846106 1,088 29 0.0001
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.