Iron Mountain Incorporated
DE ˙ DB ˙ US46284V1017
111,85 € ↑2,30 (2,10%)
2026-06-05
DEL PRIS
SecurityDE:I5M / Iron Mountain Incorporated
InstitutionRhumbline Advisers
Latest Disclosed Ownership578,543 shares
Latest Disclosed Value $ 59,092,276
Rhumbline Advisers reports 2.03% decrease in ownership of I5M / Iron Mountain Incorporated

On May 12, 2026 - Rhumbline Advisers filed a 13F-HR form disclosing ownership of 578,543 shares of Iron Mountain Incorporated (DE:I5M) valued at $51,363,048 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 590,540 shares of Iron Mountain Incorporated. This represents a change in shares of -2.03% during the quarter. The current value of the position is $64,710,035 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)
2026-05-12 2026-03-31 13F IRON MTN INC NEW COM COM 46284V101 578,543 -11,997 -2.03 59,092 20.63 0.0506
2026-02-13 2025-12-31 13F IRON MTN INC NEW COM COM 46284V101 590,540 -6,097 -1.02 48,985 -19.46 0.0396
2025-11-06 2025-09-30 13F IRON MTN INC NEW COM COM 46284V101 596,637 -23,257 -3.75 60,821 -4.34 0.0488
2025-08-12 2025-06-30 13F IRON MTN INC NEW COM COM 46284V101 619,894 -44,107 -6.64 63,582 11.29 0.0544
2025-05-29 2025-03-31 13F/A-1 IRON MTN INC NEW COM COM 46284V101 664,001 26,795 4.21 57,131 -14.70 0.0534
2025-04-08 2025-03-31 13F IRON MTN INC NEW COM COM 46284V101 664,001 26,795 57,131 0.0534
2025-05-29 2024-12-31 13F/A-1 IRON MTN INC NEW COM COM 46284V101 637,206 -32,270 -4.82 66,977 -15.81 0.0599
2025-01-30 2024-12-31 13F IRON MTN INC NEW COM COM 46284V101 637,206 -32,270 66,977 0.0599
2024-11-12 2024-09-30 13F IRON MTN INC NEW COM COM 46284V101 669,476 -2,832 -0.42 79,554 32.03 0.0718
2024-08-01 2024-06-30 13F IRON MTN INC NEW COM COM 46284V101 672,308 34,773 5.45 60,252 17.83 0.0566
2024-05-09 2024-03-31 13F IRON MTN INC NEW COM COM 46284V101 637,535 462 0.07 51,137 14.70 0.0491
2024-02-08 2023-12-31 13F IRON MTN INC NEW COM COM 46284V101 637,073 -9,986 -1.54 44,582 15.90 0.0467
2023-11-09 2023-09-30 13F IRON MTN INC NEW COM COM 46284V101 647,059 -2,074 -0.32 38,468 4.29 0.0447
2023-08-08 2023-06-30 13F IRON MTN INC NEW COM COM 46284V101 649,133 -9,059 -1.38 36,884 108,379.41 0.0413
2023-05-11 2023-03-31 13F IRON MTN INC NEW COM COM 46284V101 658,192 33,910 5.43 35 -99.89 0.0430
2023-02-14 2022-12-31 13F IRON MTN INC NEW COM COM 46284V101 624,282 43,365 7.46 31,120 21.83 0.0418
2022-11-10 2022-09-30 13F IRON MTN INC NEW COM COM 46284V101 580,917 15,482 2.74 25,543 -7.22 0.0380
2022-08-11 2022-06-30 13F IRON MTN INC NEW COM COM 46284V101 565,435 47,854 9.25 27,531 -4.00 0.0402
2022-05-12 2022-03-31 13F IRON MTN INC NEW COM COM 46284V101 517,581 -19,988 -3.72 28,679 1.95 0.0369
2022-02-10 2021-12-31 13F IRON MTN INC NEW COM COM 46284V101 537,569 18,097 3.48 28,131 24.63 0.0345
2021-11-12 2021-09-30 13F IRON MTN INC NEW COM COM 46284V101 519,472 4,489 0.87 22,571 3.57 0.0305
2021-08-05 2021-06-30 13F IRON MTN INC NEW COM COM 46284V101 514,983 -25,539 -4.72 21,794 8.94 0.0286
2021-05-06 2021-03-31 13F IRON MTN INC NEW COM COM 46284V101 540,522 -57,118 -9.56 20,005 13.55 0.0272
2021-02-10 2020-12-31 13F IRON MTN INC NEW COM COM 46284V101 597,640 4,401 0.74 17,618 10.85 0.0243
2020-11-12 2020-09-30 13F IRON MTN INC NEW COM COM 46284V101 593,239 -8,312 -1.38 15,893 1.23 0.0249
2020-08-13 2020-06-30 13F IRON MTN INC NEW COM COM 46284V101 601,551 15,693 2.68 15,700 12.60 0.0262
2020-05-06 2020-03-31 13F IRON MTN INC NEW COM COM 46284V101 585,858 86,431 17.31 13,943 -12.40 0.0292
2020-02-05 2019-12-31 13F IRON MTN INC NEW COM COM 46284V101 499,427 35,384 7.63 15,917 5.90 0.0266
2019-10-23 2019-09-30 13F IRON MTN INC NEW COM COM 46284V101 464,043 6,582 1.44 15,030 4.97 0.0275
2019-08-14 2019-06-30 13F IRON MTN INC NEW COM COM 46284V101 457,461 1,149 0.25 14,319 -11.51 0.0269
2019-05-01 2019-03-31 13F IRON MTN INC NEW COM COM 46284V101 456,312 -48,349 -9.58 16,181 -1.07 0.0313
2019-01-31 2018-12-31 13F IRON MTN INC NEW COM COM 46284V101 504,661 -724 -0.14 16,356 -6.25 0.0356
2018-11-07 2018-09-30 13F IRON MTN INC NEW COM COM 46284V101 505,385 -15,124 -2.91 17,446 -4.26 0.0337
2018-08-06 2018-06-30 13F IRON MTN INC NEW COM COM 46284V101 520,509 -39,340 -7.03 18,223 -0.95 0.0368
2018-05-02 2018-03-31 13F IRON MTN INC NEW COM COM 46284V101 559,849 15,278 2.81 18,397 -10.46 0.0384
2018-02-09 2017-12-31 13F IRON MTN INC NEW COM COM 46284V101 544,571 37,752 7.45 20,547 4.22 0.0417
2017-11-06 2017-09-30 13F IRON MTN INC NEW COM COM 46284V101 506,819 -9,235 -1.79 19,715 11.18 0.0429
2017-08-02 2017-06-30 13F IRON MTN INC NEW COM COM 46284V101 516,054 10,028 1.98 17,732 -1.76 0.0405
2017-05-02 2017-03-31 13F IRON MTN INC NEW COM COM 46284V101 506,026 25,838 5.38 18,050 15.73 0.0422
2017-01-27 2016-12-31 13F IRON MTN INC NEW COM COM 46284V101 480,188 43,272 9.90 15,597 -4.88 0.0395
2016-11-08 2016-09-30 13F IRON MTN INC NEW COM COM 46284V101 436,916 25,303 6.15 16,397 0.01 0.0452
2016-08-11 2016-06-30 13F IRON MTN INC NEW COM COM 46284V101 411,613 122,899 42.57 16,395 67.47 0.0486
2016-05-02 2016-03-31 13F IRON MOUNTAIN INC COM 46284V101 288,714 8,918 3.19 9,790 29.55 0.0304
2016-02-03 2015-12-31 13F IRON MOUNTAIN INC COM 46284V101 279,796 10,947 4.07 7,557 -9.39 0.0243
2015-11-04 2015-09-30 13F IRON MOUNTAIN INC COM 46284V101 268,849 3,097 1.17 8,340 1.24 0.0284
2015-08-04 2015-06-30 13F IRON MOUNTAIN INC COM 46284V101 265,752 -1,098 -0.41 8,238 -15.38 0.0263
2015-05-12 2015-03-31 13F IRON MOUNTAIN INC COM 46284V101 266,850 -2,935 -1.09 9,735 -6.66 0.0281
2015-02-06 2014-12-31 13F IRON MOUNTAIN INC COM 46284V101 269,785 19,632 7.85 10,430 27.71 0.0303
2014-11-12 2014-09-30 13F IRON MOUNTAIN INC COM 462846106 250,153 -3,694 -1.46 8,167 -9.25 0.0245
2014-08-06 2014-06-30 13F IRON MOUNTAIN INC COM 462846106 253,847 -4,977 -1.92 8,999 26.11 0.0264
2014-05-06 2014-03-31 13F IRON MOUNTAIN INC COM 462846106 258,824 -3,749 -1.43 7,136 -10.45 0.0212
2014-02-03 2013-12-31 13F IRON MOUNTAIN INC COM 462846106 262,573 -22,513 -7.90 7,969 3.45 0.0235
2013-11-05 2013-09-30 13F IRON MOUNTAIN INC COM 462846106 285,086 2,218 0.78 7,703 2.34 0.0239
2013-08-07 2013-06-30 13F IRON MOUNTAIN INC COM 462846106 282,868 282,868 7,527 0.0242
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.