Iron Mountain Incorporated
MX ˙ BMV ˙ US46284V1017
SecurityMX:IRM1 / Iron Mountain Incorporated
InstitutionEnsign Peak Advisors, Inc
Latest Disclosed Ownership297,330 shares
Latest Disclosed Value $ 30,369,286
Ensign Peak Advisors, Inc reports 298.47% increase in ownership of IRM1 / Iron Mountain Incorporated

On May 13, 2026 - Ensign Peak Advisors, Inc filed a 13F-HR form disclosing ownership of 297,330 shares of Iron Mountain Incorporated (MX:IRM1) valued at $30,369,286 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 74,617 shares of Iron Mountain Incorporated. This represents a change in shares of 298.47% 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 297,330 222,713 298.47 30,369 390.69 0.0566
2026-02-12 2025-12-31 13F IRON MTN INC DEL COM 46284V101 74,617 -47,970 -39.13 6,189 -50.47 0.0109
2025-11-13 2025-09-30 13F IRON MTN INC DEL COM 46284V101 122,587 -86,308 -41.32 12,497 -41.68 0.0205
2025-08-12 2025-06-30 13F IRON MTN INC DEL COM 46284V101 208,895 -18,121 -7.98 21,426 9.70 0.0367
2025-05-14 2025-03-31 13F IRON MTN INC DEL COM 46284V101 227,016 -5,184 -2.23 19,532 -19.97 0.0374
2025-02-14 2024-12-31 13F IRON MTN INC DEL COM 46284V101 232,200 7,759 3.46 24,407 -8.49 0.0434
2024-11-14 2024-09-30 13F IRON MTN INC DEL COM 46284V101 224,441 755 0.34 26,670 33.04 0.0469
2024-08-13 2024-06-30 13F IRON MTN INC DEL COM 46284V101 223,686 30,293 15.66 20,047 29.23 0.0366
2024-05-14 2024-03-31 13F IRON MTN INC DEL COM 46284V101 193,393 3,432 1.81 15,512 16.69 0.0283
2024-02-14 2023-12-31 13F IRON MTN INC DEL COM 46284V101 189,961 41,468 27.93 13,293 50.59 0.0263
2023-11-13 2023-09-30 13F IRON MTN INC DEL COM 46284V101 148,493 -14,198 -8.73 8,828 -4.51 0.0188
2023-08-14 2023-06-30 13F IRON MTN INC DEL COM 46284V101 162,691 66,790 69.64 9,244 82.18 0.0187
2023-05-15 2023-03-31 13F IRON MTN INC DEL COM 46284V101 95,901 6,565 7.35 5,074 13.95 0.0110
2023-02-13 2022-12-31 13F Iron Mountain COM 46284V101 89,336 2,900 3.36 4,453 17.15 0.0100
2022-11-14 2022-09-30 13F Iron Mountain COM 46284V101 86,436 17,710 25.77 3,801 13.60 0.0094
2022-08-12 2022-06-30 13F Iron Mountain COM 46284V101 68,726 -6,032 -8.07 3,346 -19.24 0.0080
2022-05-16 2022-03-31 13F Iron Mountain COM 46284V101 74,758 -45,120 -37.64 4,143 -33.97 0.0084
2022-02-11 2021-12-31 13F Iron Mountain COM 46284V101 119,878 83,672 231.10 6,274 298.86 0.0120
2021-11-12 2021-09-30 13F Iron Mountain COM 46284V101 36,206 -12,788 -26.10 1,573 -24.12 0.0033
2021-08-13 2021-06-30 13F Iron Mountain COM 46284V101 48,994 -34,225 -41.13 2,073 -32.67 0.0042
2021-05-12 2021-03-31 13F Iron Mountain COM 46284V101 83,219 12,817 18.21 3,079 48.46 0.0066
2021-02-12 2020-12-31 13F Iron Mountain COM 46284V101 70,402 -89,637 -56.01 2,074 -51.64 0.0047
2020-11-12 2020-09-30 13F Iron Mountain COM 46284V101 160,039 -20,346 -11.28 4,289 -8.90 0.0108
2020-08-12 2020-06-30 13F Iron Mountain COM 46284V101 180,385 11,290 6.68 4,708 17.00 0.0128
2020-05-11 2020-03-31 13F Iron Mountain COM 46284V101 169,095 -186,606 -52.46 4,024 -64.50 0.0135
2020-02-14 2019-12-31 13F Iron Mountain REIT 46284V101 355,701 355,701 11,336 0.0299
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.