Iron Mountain Incorporated
MX ˙ BMV ˙ US46284V1017
SecurityMX:IRM1 / Iron Mountain Incorporated
InstitutionNeuberger Berman Group LLC
Latest Disclosed Ownership360,751 shares
Latest Disclosed Value $ 36,847,086
Neuberger Berman Group LLC reports 16.37% decrease in ownership of IRM1 / Iron Mountain Incorporated

On May 14, 2026 - Neuberger Berman Group LLC filed a 13F-HR form disclosing ownership of 360,751 shares of Iron Mountain Incorporated (MX:IRM1) valued at $36,847,086 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 431,386 shares of Iron Mountain Incorporated. This represents a change in shares of -16.37% 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)
2026-05-14 2026-03-31 13F IRON MOUNTAIN COMMON 46284V101 360,751 -70,635 -16.37 36,847 2.97 0.0143
2026-02-13 2025-12-31 13F IRON MOUNTAIN COMMON 46284V101 431,386 15,138 3.64 35,783 -15.67 0.0266
2025-11-12 2025-09-30 13F IRON MOUNTAIN COMMON 46284V101 416,248 51,622 14.16 42,432 13.46 0.0310
2025-08-25 2025-06-30 13F/A-1 IRON MOUNTAIN COMMON 46284V101 364,626 325,110 822.73 37,400 1,000.29 0.0288
2025-08-13 2025-06-30 13F IRON MOUNTAIN COMMON 46284V101 364,626 325,110 37,400 0.0149
2025-05-13 2025-03-31 13F IRON MOUNTAIN COMMON 46284V101 39,516 -475,718 -92.33 3,400 -93.72 0.0028
2025-02-13 2024-12-31 13F IRON MOUNTAIN COMMON 46284V101 515,234 -137,382 -21.05 54,156 -30.17 0.0430
2024-11-14 2024-09-30 13F IRON MOUNTAIN COMMON 46284V101 652,616 -152 -0.02 77,550 32.56 0.0605
2024-11-14 2024-06-30 13F/A-1 IRON MOUNTAIN COMMON 46284V101 652,768 -33,599 -4.90 58,501 6.26 0.0480
2024-08-13 2024-06-30 13F IRON MOUNTAIN COMMON 46284V101 652,768 -33,599 58,501 0.0480
2024-11-14 2024-03-31 13F/A-1 IRON MOUNTAIN COMMON 46284V101 686,367 48,339 7.58 55,053 23.30 0.0455
2024-05-13 2024-03-31 13F IRON MOUNTAIN COMMON 46284V101 686,367 48,339 55,053 0.0455
2024-11-14 2023-12-31 13F/A-2 IRON MOUNTAIN COMMON 46284V101 638,028 -72,857 -10.25 44,649 5.65 0.0389
2024-02-09 2023-12-31 13F IRON MOUNTAIN COMMON 46284V101 638,028 -72,857 44,649 0.0389
2023-11-14 2023-09-30 13F IRON MOUNTAIN COMMON 46284V101 710,885 -307,653 -30.21 42,262 -26.96 0.0385
2023-08-11 2023-06-30 13F IRON MOUNTAIN COMMON 46284V101 1,018,538 -140,242 -12.10 57,865 -5.59 0.0517
2023-05-12 2023-03-31 13F IRON MOUNTAIN COMMON 46284V101 1,158,780 45,737 4.11 61,294 10.46 0.0568
2023-02-13 2022-12-31 13F IRON MOUNTAIN COMMON 46284V101 1,113,043 -254,276 -18.60 55,489 -7.83 0.0544
2022-11-15 2022-09-30 13F IRON MOUNTAIN COMMON 46284V101 1,367,319 753,405 122.72 60,202 100.91 0.0629
2022-08-15 2022-06-30 13F IRON MOUNTAIN COMMON 46284V101 613,914 485,094 376.57 29,965 315.43 0.0301
2022-05-23 2022-03-31 13F/A-1 IRON MOUNTAIN COMMON 46284V101 128,820 -1,070 -0.82 7,213 10.54 0.0061
2022-05-13 2022-03-31 13F IRON MOUNTAIN COMMON 46284V101 128,820 -1,070 6,834 0.0030
2022-02-11 2021-12-31 13F IRON MOUNTAIN COMMON 46284V101 129,890 -25,478 -16.40 6,525 -0.31 0.0051
2021-11-12 2021-09-30 13F IRON MOUNTAIN COMMON 46284V101 155,368 -16,197 -9.44 6,545 -7.78 0.0057
2021-08-13 2021-06-30 13F IRON MOUNTAIN COMMON 46284V101 171,565 46,765 37.47 7,097 52.33 0.0062
2021-05-13 2021-03-31 13F IRON MOUNTAIN COMMON 46284V101 124,800 12,211 10.85 4,659 39.24 0.0045
2021-02-10 2020-12-31 13F IRON MOUNTAIN COMMON 46284V101 112,589 19,272 20.65 3,346 34.11 0.0035
2020-11-12 2020-09-30 13F IRON MOUNTAIN INC REIT COMMON 46284V101 93,317 -1,727 -1.82 2,495 0.65 0.0030
2020-08-13 2020-06-30 13F IRON MOUNTAIN INC REIT COMMON 46284V101 95,044 6,155 6.92 2,479 17.21 0.0031
2020-05-14 2020-03-31 13F IRON MOUNTAIN INC REIT COMMON 46284V101 88,889 -17,528 -16.47 2,115 -37.65 0.0032
2020-02-12 2019-12-31 13F IRON MOUNTAIN INC REIT COMMON 46284V101 106,417 1,674 1.60 3,392 -0.03 0.0040
2019-11-13 2019-09-30 13F IRON MOUNTAIN INC REIT COMMON 46284V101 104,743 -10,195 -8.87 3,393 -5.67 0.0041
2019-08-13 2019-06-30 13F IRON MOUNTAIN INC REIT COMMON 46284V101 114,938 -5,030 -4.19 3,597 -15.44 0.0043
2019-05-13 2019-03-31 13F IRON MOUNTAIN INC REIT COMMON 46284V101 119,968 -3,451 -2.80 4,254 6.35 0.0052
2019-02-12 2018-12-31 13F IRON MOUNTAIN INC REIT COMMON 46284V101 123,419 -238,144 -65.87 4,000 -67.95 0.0056
2018-11-16 2018-09-30 13F/A-1 IRON MOUNTAIN INC REIT COMMON 46284V101 361,563 -18,043 -4.75 12,481 -6.09 0.0141
2018-11-13 2018-09-30 13F IRON MOUNTAIN INC REIT COMMON 46284V101 361,563 -18,043 12,481
2018-08-13 2018-06-30 13F IRON MOUNTAIN INC REIT COMMON 46284V101 379,606 -380,776 -50.08 13,290 -46.81 0.0147
2018-05-08 2018-03-31 13F IRON MOUNTAIN INC REIT Common 46284V101 760,382 -647,969 -46.01 24,986 -52.98 0.0286
2018-02-14 2017-12-31 13F IRON MOUNTAIN INC REIT COMMON 46284V101 1,408,351 -138,438 -8.95 53,137 -11.69 0.0611
2017-11-15 2017-09-30 13F IRON MOUNTAIN COMMON STOCK 46284V101 1,546,789 131,626 9.30 60,170 23.74 0.0753
2017-08-08 2017-06-30 13F IRON MOUNTAIN COMMON STOCK 46284V101 1,415,163 4,313 0.31 48,625 -3.38 0.0624
2017-05-10 2017-03-31 13F IRON MOUNTAIN COMMON STOCK 46284V101 1,410,850 841,849 147.95 50,325 172.31 0.0649
2017-02-06 2016-12-31 13F IRON MOUNTAIN COMMON STOCK 46284V101 569,001 -426,716 -42.86 18,481 -50.54 0.0248
2016-11-02 2016-09-30 13F IRON MOUNTAIN COMMON STOCK 46284V101 995,717 982,194 7,263.14 37,369 6,833.02 0.0507
2016-08-05 2016-06-30 13F IRON MOUNTAIN COMMON STOCK 46284V101 13,523 3,222 31.28 539 54.44 0.0007
2016-05-06 2016-03-31 13F IRON MOUNTAIN COMMON STOCK 46284V101 10,301 -199,282 -95.09 349 -93.84 0.0005
2016-01-28 2015-12-31 13F IRON MOUNTAIN COMMON STOCK 46284V101 209,583 -48,357 -18.75 5,661 -29.25 0.0074
2015-11-10 2015-09-30 13F IRON MOUNTAIN COMMON STOCK 46284V101 257,940 -13,738 -5.06 8,001 -5.00 0.0103
2015-07-31 2015-06-30 13F IRON MOUNTAIN COMMON STOCK 46284V101 271,678 -11,675 -4.12 8,422 -18.53 0.0094
2015-05-06 2015-03-31 13F IRON MOUNTAIN COMMON STOCK 46284V101 283,353 283,353 10,337 0.0110
2015-02-05 2014-12-31 13F IRON MOUNTAIN COMMON STOCK 462846106 0 -345,146 -100.00 0 -100.00
2014-11-04 2014-09-30 13F IRON MOUNTAIN COMMON STOCK 462846106 345,146 94,228 37.55 11,269 26.69 0.0116
2014-08-05 2014-06-30 13F IRON MOUNTAIN COMMON STOCK 462846106 250,918 205,837 456.59 8,895 615.61 0.0087
2014-05-05 2014-03-31 13F IRON MOUNTAIN COMMON STOCK 462846106 45,081 -49,971 -52.57 1,243 -56.92 0.0013
2014-02-11 2013-12-31 13F IRON MOUNTAIN COMMON STOCK 462846106 95,052 -788,838 -89.25 2,885 -87.92 0.0030
2013-10-29 2013-09-30 13F/A-1 IRON MOUNTAIN COMMON STOCK 462846106 883,890 -2,076,647 -70.14 23,883 -69.68 0.0265
2013-10-29 2013-09-30 13F IRON MOUNTAIN COMMON STOCK 462846106 4,099,599 118,068
2013-08-13 2013-06-30 13F IRON MOUNTAIN COMMON STOCK 462846106 2,960,537 2,960,537 78,780 0.0937
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.