Iron Mountain Incorporated
MX ˙ BMV ˙ US46284V1017
SecurityMX:IRM1 / Iron Mountain Incorporated
InstitutionAtwood & Palmer Inc
Latest Disclosed Ownership9,476 shares
Latest Disclosed Value $ 967,904
Atwood & Palmer Inc reports 0.13% increase in ownership of IRM1 / Iron Mountain Incorporated

On April 15, 2026 - Atwood & Palmer Inc filed a 13F-HR form disclosing ownership of 9,476 shares of Iron Mountain Incorporated (MX:IRM1) valued at $967,904 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 28, 2026 disclosing 9,464 shares of Iron Mountain Incorporated. This represents a change in shares of 0.13% 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)
2026-04-15 2026-03-31 13F IRON MTN INC DEL COM 46284V101 9,476 12 0.13 968 23.18 0.0546
2026-01-28 2025-12-31 13F IRON MTN INC DEL COM 46284V101 9,464 10 0.11 785 -18.48 0.0446
2025-10-15 2025-09-30 13F IRON MTN INC DEL COM 46284V101 9,454 9 0.10 964 -0.52 0.0566
2025-07-08 2025-06-30 13F IRON MTN INC DEL COM 46284V101 9,445 1,195 14.48 969 36.53 0.0606
2025-04-15 2025-03-31 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 710 -18.22 0.0492
2025-01-16 2024-12-31 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 867 -11.53 0.0594
2024-10-07 2024-09-30 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 980 32.61 0.0666
2024-07-10 2024-06-30 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 739 11.80 0.0560
2024-04-10 2024-03-31 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 662 14.56 0.0502
2024-01-12 2023-12-31 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 577 17.76 0.0467
2023-10-20 2023-09-30 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 490 4.70 0.0430
2023-07-18 2023-06-30 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 469 7.34 0.0419
2023-04-21 2023-03-31 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 437 6.08 0.0410
2023-01-31 2022-12-31 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 411 13.22 0.0372
2022-10-12 2022-09-30 13F IRON MTN INC DEL COM 46284V101 8,250 0 0.00 363 -9.70 0.0360
2022-07-21 2022-06-30 13F IRON MTN INC COM 46284V101 8,250 -80 -0.96 402 -12.99 0.0392
2022-04-29 2022-03-31 13F IRON MTN INC COM 46284V101 8,330 0 0.00 462 5.96 0.0399
2022-01-24 2021-12-31 13F IRON MTN INC COM 46284V101 8,330 0 0.00 436 20.44 0.0365
2021-10-29 2021-09-30 13F/A-1 IRON MTN INC COM 46284V101 8,330 0 0.00 362 2.55 0.0323
2021-10-19 2021-09-30 13F IRON MTN INC COM 46284V101 8,330 0 362 0.0323
2021-07-26 2021-06-30 13F IRON MTN INC COM 46284V101 8,330 0 0.00 353 14.61 0.0317
2021-04-26 2021-03-31 13F IRON MTN INC COM 46284V101 8,330 80 0.97 308 26.75 0.0296
2021-02-04 2020-12-31 13F IRON MTN INC COM 46284V101 8,250 0 0.00 243 9.95 0.0261
2020-10-28 2020-09-30 13F IRON MTN INC COM 46284V101 8,250 0 0.00 221 2.79 0.0278
2020-07-24 2020-06-30 13F IRON MTN INC COM 46284V101 8,250 0 0.00 215 9.69 0.0291
2020-04-20 2020-03-31 13F IRON MTN INC COM 46284V101 8,250 0 0.00 196 -25.48 0.0308
2020-02-05 2019-12-31 13F IRON MTN INC COM 46284V101 8,250 0 0.00 263 -1.50 0.0338
2019-10-21 2019-09-30 13F IRON MTN INC COM 46284V101 8,250 8,000 3,200.00 267 3,237.50 0.0360
2019-07-17 2019-06-30 13F IRON MTN INC COM 46284V101 250 0 0.00 8 -11.11 0.0011
2019-04-23 2019-03-31 13F IRON MTN INC COM 46284V101 250 0 0.00 9 12.50 0.0013
2019-02-01 2018-12-31 13F IRON MTN INC COM 46284V101 250 0 0.00 8 -11.11 0.0013
2018-10-29 2018-09-30 13F IRON MTN INC COM 46284V101 250 0 0.00 9 0.00 0.0012
2018-07-19 2018-06-30 13F IRON MTN INC COM 46284V101 250 0 0.00 9 12.50 0.0012
2018-04-30 2018-03-31 13F IRON MTN INC COM 46284V101 250 250 8 0.0011
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.