Iron Mountain Incorporated
DE ˙ DB ˙ US46284V1017
111,85 € ↑2,30 (2,10%)
2026-06-05
DEL PRIS
SecurityDE:I5M / Iron Mountain Incorporated
InstitutionFlagship Harbor Advisors, Llc
Latest Disclosed Ownership3,987 shares
Latest Disclosed Value $ 407,235
Flagship Harbor Advisors, Llc reports 186.22% increase in ownership of I5M / Iron Mountain Incorporated

On April 28, 2026 - Flagship Harbor Advisors, Llc filed a 13F-HR form disclosing ownership of 3,987 shares of Iron Mountain Incorporated (DE:I5M) valued at $353,966 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 21, 2026 disclosing 1,393 shares of Iron Mountain Incorporated. This represents a change in shares of 186.22% during the quarter. The current value of the position is $445,946 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)
2026-04-28 2026-03-31 13F IRON MTN INC DEL COM 46284V101 3,987 2,594 186.22 407 253.91 0.0179
2026-01-21 2025-12-31 13F IRON MOUNTAIN Common Stock 46284V101 1,393 -6,552 -82.47 116 -85.78 0.0055
2025-11-05 2025-09-30 13F IRON MTN INC DEL COM 46284V101 7,945 -344 -4.15 810 -4.82 0.0352
2025-08-04 2025-06-30 13F IRON MTN INC DEL COM 46284V101 8,289 -251 -2.94 850 15.80 0.0403
2025-04-22 2025-03-31 13F IRON MTN INC DEL COM 46284V101 8,540 -366 -4.11 735 -21.58 0.0386
2025-01-21 2024-12-31 13F IRON MTN INC DEL COM 46284V101 8,906 977 12.32 936 -0.64 0.0492
2024-10-21 2024-09-30 13F IRON MTN INC DEL COM 46284V101 7,929 1,646 26.20 942 67.32 0.0517
2025-12-02 2024-06-30 13F IRON MTN INC DEL COM 46284V101 6,283 -12 -0.19 563 11.71 0.0338
2024-04-16 2024-03-31 13F IRON MTN INC DEL COM 46284V101 6,295 -91 -1.42 505 13.00 0.0324
2024-01-10 2023-12-31 13F IRON MTN INC DEL COM 46284V101 6,386 -289 -4.33 447 12.63 0.0325
2023-10-17 2023-09-30 13F IRON MTN INC DEL COM 46284V101 6,675 280 4.38 397 9.09 0.0330
2023-07-11 2023-06-30 13F IRON MTN INC DEL COM 46284V101 6,395 377 6.26 363 14.15 0.0300
2023-04-12 2023-03-31 13F IRON MTN INC DEL COM 46284V101 6,018 315 5.52 318 11.97 0.0300
2023-01-13 2022-12-31 13F IRON MTN INC DEL COM 46284V101 5,703 -42 -0.73 284 12.25 0.0291
2022-10-13 2022-09-30 13F IRON MTN INC DEL COM 46284V101 5,745 116 2.06 253 -7.66 0.0293
2022-07-13 2022-06-30 13F IRON MTN INC COM 46284V101 5,629 818 17.00 274 2.62 0.0308
2022-04-13 2022-03-31 13F IRON MTN INC COM 46284V101 4,811 47 0.99 267 7.23 0.0257
2022-02-17 2021-12-31 13F/A-1 IRON MTN INC COM 46284V101 4,764 -1,470 -23.58 249 -5.68 0.0236
2022-02-10 2021-12-31 13F IRON MTN INC COM 46284V101 4,764 -1,470 249 0.0236
2021-11-01 2021-09-30 13F IRON MTN INC COM 46284V101 6,234 0 0.00 264 0.00 0.0284
2021-07-26 2021-06-30 13F IRON MTN INC COM 46284V101 6,234 -222 -3.44 264 10.46 0.0283
2021-05-03 2021-03-31 13F IRON MTN INC COM 46284V101 6,456 6,456 239 0.0271
2021-02-08 2020-12-31 13F IRON MOUNTAIN Common Stock 46284V101 0 -4,487 -100.00 0 -100.00
2020-10-13 2020-09-30 13F IRON MOUNTAIN Common Stock 46284V101 4,487 1,879 72.05 120 76.47 0.0162
2020-07-31 2020-06-30 13F IRON MOUNTAIN Common Stock 46284V101 2,608 1,281 96.53 68 112.50 0.0100
2020-05-12 2020-03-31 13F IRON MOUNTAIN Common Stock 46284V101 1,327 25 1.92 32 -23.81 0.0064
2020-02-14 2019-12-31 13F IRON MOUNTAIN Common Stock 46284V101 1,302 24 1.88 42 2.44 0.0074
2019-10-22 2019-09-30 13F IRON MOUNTAIN Common Stock 46284V101 1,278 638 99.69 41 105.00 0.0080
2019-07-22 2019-06-30 13F IRON MOUNTAIN Common Stock 46284V101 640 640 20 0.0042
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.