Iron Mountain Incorporated
US ˙ NYSE ˙ US46284V1017

SecurityIRM / Iron Mountain Incorporated
InstitutionAviva Plc
Latest Disclosed Ownership263,200 shares
Latest Disclosed Value $ 26,883,248
Aviva Plc reports 2.76% increase in ownership of IRM / Iron Mountain Incorporated

On May 14, 2026 - Aviva Plc filed a 13F-HR form disclosing ownership of 263,200 shares of Iron Mountain Incorporated (US:IRM) valued at $26,883,248 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 256,125 shares of Iron Mountain Incorporated. This represents a change in shares of 2.76% during the quarter. The current value of the position is $33,676,440 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)
2026-05-14 2026-03-31 13F IRON MTN INC DEL COM 46284V101 263,200 7,075 2.76 26,883 26.54 0.0451
2026-02-12 2025-12-31 13F IRON MTN INC DEL COM 46284V101 256,125 13,676 5.64 21,246 -14.04 0.0358
2025-11-13 2025-09-30 13F IRON MTN INC DEL COM 46284V101 242,449 14,210 6.23 24,715 5.57 0.0449
2025-08-07 2025-06-30 13F IRON MTN INC DEL COM 46284V101 228,239 -125,947 -35.56 23,410 -23.18 0.0483
2025-05-15 2025-03-31 13F IRON MTN INC DEL COM 46284V101 354,186 -75,287 -17.53 30,474 -32.49 0.0735
2025-02-13 2024-12-31 13F IRON MTN INC DEL COM 46284V101 429,473 -8,126 -1.86 45,142 -13.19 0.1172
2024-11-14 2024-09-30 13F IRON MTN INC DEL COM 46284V101 437,599 -17,666 -3.88 52,000 27.45 0.1347
2024-08-02 2024-06-30 13F IRON MTN INC DEL COM 46284V101 455,265 116,619 34.44 40,801 50.21 0.1131
2024-05-14 2024-03-31 13F IRON MTN INC DEL COM 46284V101 338,646 4,490 1.34 27,163 16.16 0.0894
2024-02-09 2023-12-31 13F IRON MTN INC DEL COM 46284V101 334,156 18,869 5.98 23,384 24.76 0.0838
2023-11-13 2023-09-30 13F IRON MTN INC DEL COM 46284V101 315,287 -51,391 -14.02 18,744 -10.04 0.0788
2023-08-10 2023-06-30 13F IRON MTN INC DEL COM 46284V101 366,678 -48,955 -11.78 20,835 -5.26 0.0848
2023-05-12 2023-03-31 13F IRON MTN INC DEL COM 46284V101 415,633 196,371 89.56 21,991 101.20 0.0996
2023-02-14 2022-12-31 13F/A-2 IRON MTN INC DEL COM 46284V101 219,262 -70,379 -24.30 10,930 -14.18 0.0538
2023-02-10 2022-12-31 13F/A-1 IRON MTN INC DEL COM 46284V101 219,262 -70,379 2,083 0.0099
2023-02-09 2022-12-31 13F IRON MTN INC DEL COM 46284V101 219,262 -70,379 11 0.0525
2022-11-14 2022-09-30 13F IRON MTN INC DEL COM 46284V101 289,641 54,733 23.30 12,736 11.35 0.0734
2022-08-04 2022-06-30 13F IRON MTN INC COM 46284V101 234,908 131,014 126.10 11,438 98.68 0.0609
2022-05-13 2022-03-31 13F IRON MTN INC COM 46284V101 103,894 16,162 18.42 5,757 25.40 0.0288
2022-02-10 2021-12-31 13F IRON MTN INC COM 46284V101 87,732 -125 -0.14 4,591 20.28 0.0192
2021-11-12 2021-09-30 13F IRON MTN INC COM 46284V101 87,857 -4,858 -5.24 3,817 -2.73 0.0170
2021-08-10 2021-06-30 13F IRON MTN INC COM 46284V101 92,715 -2,273 -2.39 3,924 11.60 0.0172
2021-05-13 2021-03-31 13F IRON MTN INC COM 46284V101 94,988 -166 -0.17 3,516 25.35 0.0172
2021-02-10 2020-12-31 13F IRON MTN INC COM 46284V101 95,154 2,268 2.44 2,805 12.74 0.0146
2020-11-12 2020-09-30 13F IRON MTN INC COM 46284V101 92,886 -3,038 -3.17 2,488 -0.64 0.0147
2020-08-13 2020-06-30 13F/A-1 IRON MTN INC COM 46284V101 95,924 -4,587 -4.56 2,504 4.68 0.0156
2020-08-13 2020-06-30 13F IRON MTN INC COM 46284V101 95,924 -4,587 2,504 7,580.6820
2020-05-14 2020-03-31 13F IRON MTN INC COM 46284V101 100,511 103 0.10 2,392 -25.25 0.0175
2020-02-10 2019-12-31 13F IRON MTN INC COM 46284V101 100,408 -687 -0.68 3,200 -2.26 0.0194
2019-11-12 2019-09-30 13F IRON MTN INC COM 46284V101 101,095 -3,826 -3.65 3,274 -0.30 0.0222
2019-07-30 2019-06-30 13F IRON MTN INC COM 46284V101 104,921 -2,657 -2.47 3,284 -13.92 0.0226
2019-05-14 2019-03-31 13F IRON MTN INC COM 46284V101 107,578 1,542 1.45 3,815 11.00 0.0256
2019-02-12 2018-12-31 13F IRON MTN INC COM 46284V101 106,036 -31,205 -22.74 3,437 -27.46 0.0256
2018-11-13 2018-09-30 13F IRON MTN INC COM 46284V101 137,241 -4,380 -3.09 4,738 -4.44 0.0260
2018-08-01 2018-06-30 13F IRON MTN INC COM 46284V101 141,621 832 0.59 4,958 7.18 0.0293
2018-05-14 2018-03-31 13F IRON MTN INC COM 46284V101 140,789 -12,409 -8.10 4,626 -19.97 0.0283
2018-02-13 2017-12-31 13F IRON MTN INC COM 46284V101 153,198 -12,818 -7.72 5,780 -10.50 0.0327
2017-11-13 2017-09-30 13F IRON MTN INC COM 46284V101 166,016 2,360 1.44 6,458 14.81 0.0348
2017-08-07 2017-06-30 13F IRON MTN INC COM 46284V101 163,656 15,270 10.29 5,625 6.27 0.0314
2017-05-15 2017-03-31 13F IRON MTN INC COM 46284V101 148,386 -8,499 -5.42 5,293 3.85 0.0303
2017-02-13 2016-12-31 13F IRON MTN INC COM 46284V101 156,885 8,789 5.93 5,097 -8.29 0.0304
2016-11-14 2016-09-30 13F IRON MTN INC COM 46284V101 148,096 4,936 3.45 5,558 -2.53 0.0347
2016-08-05 2016-06-30 13F IRON MTN INC COM 46284V101 143,160 47,410 49.51 5,702 75.61 0.0391
2016-05-12 2016-03-31 13F IRON MTN INC COM 46284V101 95,750 828 0.87 3,247 26.64 0.0241
2016-02-11 2015-12-31 13F IRON MTN INC COM 46284V101 94,922 -909 -0.95 2,564 -13.76 0.0194
2015-11-12 2015-09-30 13F IRON MTN INC COM 46284V101 95,831 -3,022 -3.06 2,973 -2.97 0.0246
2015-08-06 2015-06-30 13F IRON MTN INC COM 46284V101 98,853 -510 -0.51 3,064 -15.48 0.0217
2015-05-14 2015-03-31 13F IRON MTN INC COM 46284V101 99,363 99,363 3,625 0.0248
2015-02-05 2014-12-31 13F/A-1 IRON MTN COM 462846106 0 -70,094 -100.00 0 -100.00
2014-11-13 2014-09-30 13F IRON MTN COM 462846106 70,094 -350 -0.50 2,289 -8.33 0.0181
2014-08-13 2014-06-30 13F IRON MTN COM 462846106 70,444 -50 -0.07 2,497 28.45 0.0191
2014-05-14 2014-03-31 13F IRON MTN COM 462846106 70,494 3,310 4.93 1,944 -4.66 0.0158
2014-02-13 2013-12-31 13F IRON MTN COM 462846106 67,184 2,365 3.65 2,039 16.45 0.0170
2013-11-13 2013-09-30 13F IRON MTN COM 462846106 64,819 11,939 22.58 1,751 24.45 0.0154
2013-08-01 2013-06-30 13F IRON MTN COM 462846106 52,880 52,880 1,407 0.0142
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.