Iron Mountain Incorporated
MX ˙ BMV ˙ US46284V1017
SecurityMX:IRM1 / Iron Mountain Incorporated
InstitutionProShare Advisors LLC
Latest Disclosed Ownership54,548 shares
Latest Disclosed Value $ 5,571,531
ProShare Advisors LLC reports 18.03% decrease in ownership of IRM1 / Iron Mountain Incorporated

On April 24, 2026 - ProShare Advisors LLC filed a 13F-HR form disclosing ownership of 54,548 shares of Iron Mountain Incorporated (MX:IRM1) valued at $5,571,531 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 66,548 shares of Iron Mountain Incorporated. This represents a change in shares of -18.03% during the quarter.

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)
2026-04-24 2026-03-31 13F IRON MTN INC DEL COM 46284V101 54,548 -12,000 -18.03 5,572 0.92 0.0082
2026-02-06 2025-12-31 13F IRON MTN INC DEL COM 46284V101 66,548 4,682 7.57 5,520 -12.46 0.0097
2025-11-06 2025-09-30 13F IRON MTN INC DEL COM 46284V101 61,866 996 1.64 6,307 1.01 0.0132
2025-08-07 2025-06-30 13F IRON MTN INC DEL COM 46284V101 60,870 4,694 8.36 6,243 29.17 0.0125
2025-05-08 2025-03-31 13F IRON MTN INC DEL COM 46284V101 56,176 2,747 5.14 4,833 -13.93 0.0109
2025-02-14 2024-12-31 13F IRON MTN INC DEL COM 46284V101 53,429 3,630 7.29 5,616 -5.10 0.0128
2024-11-14 2024-09-30 13F IRON MTN INC DEL COM 46284V101 49,799 -1,952 -3.77 5,918 27.60 0.0145
2024-08-13 2024-06-30 13F IRON MTN INC DEL COM 46284V101 51,751 2,991 6.13 4,638 18.56 0.0124
2024-05-08 2024-03-31 13F IRON MTN INC DEL COM 46284V101 48,760 -842 -1.70 3,911 12.68 0.0104
2024-02-14 2023-12-31 13F IRON MTN INC DEL COM 46284V101 49,602 -4,454 -8.24 3,471 8.03 0.0106
2023-11-13 2023-09-30 13F IRON MTN INC DEL COM 46284V101 54,056 -2,657 -4.68 3,214 -0.28 0.0100
2023-08-10 2023-06-30 13F IRON MTN INC DEL COM 46284V101 56,713 603 1.07 3,222 8.56 0.0093
2023-05-26 2023-03-31 13F/A-1 IRON MTN INC DEL COM 46284V101 56,110 -15,822 -22.00 2,969 -17.21 0.0091
2023-05-12 2023-03-31 13F IRON MTN INC DEL COM 46284V101 56,110 -15,822 2,969 0.0094
2023-02-02 2022-12-31 13F IRON MTN INC DEL COM 46284V101 71,932 1,750 2.49 3,586 16.17 0.0126
2022-11-07 2022-09-30 13F IRON MTN INC DEL COM 46284V101 70,182 -6,328 -8.27 3,086 -17.18 0.0118
2022-08-01 2022-06-30 13F IRON MTN INC COM 46284V101 76,510 -23,259 -23.31 3,726 -32.59 0.0124
2022-05-10 2022-03-31 13F IRON MTN INC COM 46284V101 99,769 -7,790 -7.24 5,527 -1.81 0.0119
2022-02-08 2021-12-31 13F IRON MTN INC COM 46284V101 107,559 18,283 20.48 5,629 45.11 0.0110
2021-11-12 2021-09-30 13F IRON MTN INC COM 46284V101 89,276 1,317 1.50 3,879 4.22 0.0109
2021-08-13 2021-06-30 13F IRON MTN INC COM 46284V101 87,959 -13,892 -13.64 3,722 -1.27 0.0109
2021-05-14 2021-03-31 13F IRON MTN INC COM 46284V101 101,851 5,881 6.13 3,770 33.26 0.0119
2021-02-09 2020-12-31 13F IRON MTN INC COM 46284V101 95,970 2,691 2.88 2,829 13.21 0.0105
2020-11-13 2020-09-30 13F IRON MTN INC COM 46284V101 93,279 -423 -0.45 2,499 2.17 0.0116
2020-08-03 2020-06-30 13F IRON MTN INC COM 46284V101 93,702 -5,339 -5.39 2,446 3.78 0.0131
2020-05-15 2020-03-31 13F IRON MTN INC COM 46284V101 99,041 -54,318 -35.42 2,357 -51.78 0.0169
2020-02-12 2019-12-31 13F IRON MTN INC COM 46284V101 153,359 36,921 31.71 4,888 29.62 0.0226
2019-11-12 2019-09-30 13F IRON MTN INC COM 46284V101 116,438 -2,295 -1.93 3,771 1.48 0.0211
2019-08-13 2019-06-30 13F IRON MTN INC COM 46284V101 118,733 -5,270 -4.25 3,716 -15.49 0.0222
2019-05-15 2019-03-31 13F IRON MTN INC COM 46284V101 124,003 1,203 0.98 4,397 10.48 0.0263
2019-02-14 2018-12-31 13F IRON MTN INC COM 46284V101 122,800 9,687 8.56 3,980 1.92 0.0279
2018-11-14 2018-09-30 13F IRON MTN INC COM 46284V101 113,113 -10,268 -8.32 3,905 -9.61 0.0265
2018-08-13 2018-06-30 13F IRON MTN INC COM 46284V101 123,381 -4,542 -3.55 4,320 2.76 0.0290
2018-05-14 2018-03-31 13F IRON MTN INC COM 46284V101 127,923 2,454 1.96 4,204 -11.20 0.0274
2018-02-14 2017-12-31 13F IRON MTN INC COM 46284V101 125,469 25,151 25.07 4,734 21.32 0.0328
2017-11-13 2017-09-30 13F IRON MTN INC COM 46284V101 100,318 419 0.42 3,902 13.66 0.0359
2017-08-11 2017-06-30 13F IRON MTN INC COM 46284V101 99,899 -1,143 -1.13 3,433 -4.74 0.0342
2017-05-12 2017-03-31 13F/A-2 IRON MTN INC COM 46284V101 101,042 -26,745 -20.93 3,604 -13.18 0.0377
2017-05-08 2017-03-31 13F/A-1 IRON MTN INC COM 46284V101 5,261 -95,781 3,604 0.0377
2017-04-25 2017-03-31 13F IRON MTN INC COM 46284V101 5,261 3,604
2017-02-13 2016-12-31 13F IRON MTN INC COM 46284V101 127,787 25,198 24.56 4,151 7.82 0.0460
2016-11-10 2016-09-30 13F IRON MTN INC COM 46284V101 102,589 -13,967 -11.98 3,850 -17.06 0.0538
2016-08-12 2016-06-30 13F IRON MTN INC COM 46284V101 116,556 4,277 3.81 4,642 21.93 0.0598
2016-05-06 2016-03-31 13F IRON MTN INC COM 46284V101 112,279 -28,892 -20.47 3,807 -0.16 0.0524
2016-02-05 2015-12-31 13F IRON MTN INC COM 46284V101 141,171 54,220 62.36 3,813 41.38 0.0462
2015-11-06 2015-09-30 13F IRON MTN INC COM 46284V101 86,951 -3,796 -4.18 2,697 -4.12 0.0379
2015-08-11 2015-06-30 13F IRON MTN INC COM 46284V101 90,747 -12,337 -11.97 2,813 -25.21 0.0389
2015-05-08 2015-03-31 13F IRON MTN INC COM 46284V101 103,084 103,084 3,761 0.0443
2015-01-30 2014-12-31 13F IRON MTN COM 462846106 0 -26,203 -100.00 0 -100.00
2014-11-06 2014-09-30 13F IRON MTN COM 462846106 26,203 -2,134 -7.53 856 -14.83 0.0113
2014-08-08 2014-06-30 13F IRON MTN COM 462846106 28,337 -2,521 -8.17 1,005 18.10 0.0130
2014-05-07 2014-03-31 13F IRON MTN COM 462846106 30,858 2,126 7.40 851 -2.41 0.0106
2014-02-04 2013-12-31 13F IRON MTN COM 462846106 28,732 15,197 112.28 872 138.25 0.0130
2013-11-07 2013-09-30 13F IRON MTN COM 462846106 13,535 -11,778 -46.53 366 -45.70 0.0087
2013-07-25 2013-06-30 13F IRON MTN COM 462846106 25,313 25,313 674 0.0132
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.