Iron Mountain Incorporated
MX ˙ BMV ˙ US46284V1017
SecurityMX:IRM1 / Iron Mountain Incorporated
InstitutionAPG Asset Management N.V.
Latest Disclosed Ownership150,916 shares
Latest Disclosed Value $ 13,378,372
APG Asset Management N.V. reports 2.12% decrease in ownership of IRM1 / Iron Mountain Incorporated

On May 13, 2026 - APG Asset Management N.V. filed a 13F-HR form disclosing ownership of 150,916 shares of Iron Mountain Incorporated (MX:IRM1) valued at $13,378,372 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 154,181 shares of Iron Mountain Incorporated. This represents a change in shares of -2.12% 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)
2026-05-13 2026-03-31 13F IRON MTN INC DEL COM 46284V101 150,916 -3,265 -2.12 13,378 22.86 0.0424
2026-02-12 2025-12-31 13F IRON MTN INC DEL COM 46284V101 154,181 -10,219 -6.22 10,890 -23.65 0.0309
2025-11-12 2025-09-30 13F IRON MTN INC DEL COM 46284V101 164,400 0 0.00 14,263 -0.72 0.0400
2025-08-12 2025-06-30 13F IRON MTN INC DEL COM 46284V101 164,400 6,200 3.92 14,365 14.01 0.0425
2025-05-14 2025-03-31 13F IRON MTN INC DEL COM 46284V101 158,200 -1,000 -0.63 12,601 -22.02 0.0391
2025-02-13 2024-12-31 13F IRON MTN INC DEL COM 46284V101 159,200 159,200 16,160 0.0450
2024-11-14 2024-09-30 13F IRON MTN INC DEL COM 46284V101 0 -37,044 -100.00 0 -100.00
2024-08-14 2024-06-30 13F IRON MTN INC DEL COM 46284V101 37,044 24,100 186.19 3,098 222.27 0.0055
2024-05-14 2024-03-31 13F IRON MTN INC DEL COM 46284V101 12,944 800 6.59 961 24.97 0.0017
2024-02-13 2023-12-31 13F IRON MTN INC DEL COM 46284V101 12,144 1,839 17.85 769 25.65 0.0015
2023-11-14 2023-09-30 13F IRON MTN INC DEL COM 46284V101 10,305 -1,100 -9.64 613 3.20 0.0013
2023-08-14 2023-06-30 13F IRON MTN INC DEL COM 46284V101 11,405 0 0.00 594 6.85 0.0012
2023-05-12 2023-03-31 13F IRON MTN INC DEL COM 46284V101 11,405 -16,970 -59.81 555 55,400.00 0.0012
2023-02-14 2022-12-31 13F IRON MTN INC DEL COM 46284V101 28,375 16,970 148.79 1 -99.80 0.0027
2022-11-14 2022-09-30 13F IRON MTN INC DEL COM 46284V101 11,405 -400 -3.39 512 -6.91 0.0013
2022-08-12 2022-06-30 13F IRON MTN INC COM 46284V101 11,805 -6,400 -35.16 550 -39.36 0.0013
2022-05-12 2022-03-31 13F IRON MTN INC COM 46284V101 18,205 2,100 13.04 907 22.40 0.0017
2022-02-11 2021-12-31 13F IRON MTN INC COM 46284V101 16,105 -11,800 -42.29 741 -29.16 0.0013
2021-11-15 2021-09-30 13F/A-1 IRON MTN INC COM 46284V101 27,905 -10,200 -26.77 1,046 -23.09 0.0019
2021-11-15 2021-09-30 13F IRON MTN INC COM 46284V101 27,905 -10,200 1,046 0.0019
2021-08-13 2021-06-30 13F IRON MTN INC COM 46284V101 38,105 -200 -0.52 1,360 12.77 0.0023
2021-05-14 2021-03-31 13F IRON MTN INC COM 46284V101 38,305 -115,736 -75.13 1,206 -67.50 0.0021
2021-02-12 2020-12-31 13F IRON MTN INC COM 46284V101 154,041 -10,732 -6.51 3,711 -1.41 0.0061
2020-11-12 2020-09-30 13F IRON MTN INC COM 46284V101 164,773 -12,000 -6.79 3,764 -8.37 0.0065
2020-08-14 2020-06-30 13F IRON MTN INC COM 46284V101 176,773 -17,100 -8.82 4,108 -10.97 0.0075
2020-05-19 2020-03-31 13F/A-2 IRON MTN INC COM 46284V101 193,873 61,197 46.13 4,614 22.48 0.0090
2020-05-15 2020-03-31 13F/A-1 IRON MTN INC COM 46284V101 193,873 0 4,614 0.0091
2020-02-13 2019-12-31 13F IRON MTN INC COM 46284V101 132,676 0 0.00 3,767 -4.44 0.0061
2019-11-08 2019-09-30 13F IRON MTN INC COM 46284V101 132,676 132,676 3,942 0.0065
2017-05-01 2017-03-31 13F IRON MTN INC COM 46284V101 0 -125,779 -100.00 0 -100.00
2017-01-30 2016-12-31 13F IRON MTN INC COM 46284V101 125,779 0 0.00 3,873 -17.94 0.0073
2016-10-31 2016-09-30 13F IRON MTN INC COM 46284V101 125,779 0 0.00 4,720 -5.79 0.0083
2016-08-11 2016-06-30 13F IRON MTN INC COM 46284V101 125,779 41,700 49.60 5,010 75.73 0.0094
2016-05-16 2016-03-31 13F IRON MTN INC COM 46284V101 84,079 -153,062 -64.54 2,851 -55.49 0.0059
2016-02-17 2015-12-31 13F/A-1 IRON MTN INC COM 46284V101 237,141 -35,713 -13.09 6,405 -24.33 0.0148
2016-02-16 2015-12-31 13F IRON MTN INC COM 46284V101 239,400 6,405
2015-11-12 2015-09-30 13F IRON MTN INC COM 46284V101 272,854 -19,851 -6.78 8,464 -6.72 0.0194
2015-08-12 2015-06-30 13F IRON MTN INC COM 46284V101 292,705 0 0.00 9,074 -15.02 0.0182
2015-05-14 2015-03-31 13F IRON MTN INC COM 46284V101 292,705 -119,008 -28.91 10,678 -32.91 0.0221
2015-02-09 2014-12-31 13F IRON MTN COM 462846106 411,713 47,041 12.90 15,917 33.68 0.0305
2014-11-12 2014-09-30 13F IRON MTN COM 462846106 364,672 6,119 1.71 11,907 -6.33 0.0241
2014-08-11 2014-06-30 13F IRON MTN COM 462846106 358,553 65,240 22.24 12,711 57.18 0.0271
2014-04-30 2014-03-31 13F IRON MTN COM 462846106 293,313 165,035 128.65 8,087 107.73 0.0211
2014-02-20 2013-12-31 13F/A-1 IRON MTN COM 462846106 128,278 -2,905 -2.21 3,893 9.82 0.0114
2014-02-12 2013-12-31 13F IRON MTN COM 462846106 128,278 3,893
2013-11-13 2013-09-30 13F IRON MTN COM 462846106 131,183 -57,574 -30.50 3,545 -29.42 0.0112
2013-08-14 2013-06-30 13F IRON MTN COM 462846106 188,757 188,757 5,023 0.0157
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.