Iron Mountain Incorporated
MX ˙ BMV ˙ US46284V1017
SecurityMX:IRM1 / Iron Mountain Incorporated
InstitutionNomura Holdings Inc
Latest Disclosed Ownership9,655 shares
Latest Disclosed Value $ 986,162
Nomura Holdings Inc ownership in IRM1 / Iron Mountain Incorporated

On May 15, 2026 - Nomura Holdings Inc filed a 13F-HR form disclosing ownership of 9,655 shares of Iron Mountain Incorporated (MX:IRM1) valued at $986,162 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 14,831 shares of Iron Mountain Incorporated. This represents a change in shares of -34.90% during the quarter.

Nomura Holdings Inc has a history of taking positions in derivatives of the underlying security (IRM1) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:IRM1 / Iron Mountain Incorporated Historical Put/Call Ratio
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)
2026-05-15 2026-03-31 13F IRON MTN INC DEL COM 46284V101 9,655 -5,176 -34.90 986 -19.84 0.0026
2026-02-17 2025-12-31 13F IRON MTN INC DEL COM 46284V101 14,831 -121 -0.81 1,230 -19.29 0.0016
2025-11-14 2025-09-30 13F IRON MTN INC DEL COM 46284V101 14,952 12,180 439.39 1,524 436.62 0.0024
2025-08-14 2025-06-30 13F IRON MTN INC DEL COM 46284V101 2,772 -71,742 -96.28 284 -95.57 0.0005
2025-05-15 2025-03-31 13F IRON MTN INC DEL COM 46284V101 74,514 30,780 70.38 6,411 39.49 0.0120
2025-02-14 2024-12-31 13F IRON MTN INC DEL COM 46284V101 43,734 20,551 88.65 4,597 66.88 0.0062
2025-01-13 2024-09-30 13F/A-1 IRON MTN INC DEL COM 46284V101 23,183 18,943 446.77 2,755 626.65 0.0063
2024-11-14 2024-09-30 13F IRON MTN INC DEL COM 46284V101 23,183 18,943 2,755 0.0063
2024-08-14 2024-06-30 13F IRON MTN INC DEL COM 46284V101 4,240 4,240 380 0.0007
2024-05-15 2024-03-31 13F IRON MTN INC DEL COM 46284V101 0 -51,817 -100.00 0 -100.00
2024-03-27 2023-12-31 13F/A-1 IRON MTN INC DEL COM 46284V101 51,817 51,817 3,626 0.0098
2024-02-14 2023-12-31 13F IRON MTN INC DEL COM 46284V101 51,817 51,817 3,626 0.0075
2021-11-15 2021-09-30 13F IRON MOUNTAIN CMN 46284V101 0 -10,070 -100.00 0 -100.00
2021-08-16 2021-06-30 13F IRON MOUNTAIN CMN 46284V101 10,070 10,070 426 0.0011
2021-05-17 2021-03-31 13F IRON MOUNTAIN CMN 46284V101 0 -13,357 -100.00 0 -100.00 0.0000
2021-02-16 2020-12-31 13F IRON MOUNTAIN CMN 46284V101 13,357 13,357 0 0.0007
2020-11-12 2020-09-30 13F IRON MOUNTAIN CMN 46284V101 0 -22,260 -100.00 0 -100.00
2020-08-14 2020-06-30 13F IRON MOUNTAIN CMN 46284V101 22,260 -19,274 -46.41 580 -54.62 0.0020
2019-08-23 2019-06-30 13F/A-1 IRON MOUNTAIN CMN 46284V101 41,534 70 0.17 1,278 -13.77 0.0057
2019-08-14 2019-06-30 13F IRON MOUNTAIN CMN 46284V101 41,534 70 1,278
2019-05-14 2019-03-31 13F IRON MOUNTAIN CMN 46284V101 41,464 34,749 517.48 1,482 582.95 0.0063
2019-02-14 2018-12-31 13F IRON MOUNTAIN CMN 46284V101 6,715 -35,047 -83.92 217 -84.89 0.0008
2018-11-14 2018-09-30 13F IRON MOUNTAIN CMN 46284V101 41,762 41,762 521.92 1,436 561.75 0.0050
2018-08-17 2018-06-30 13F/A-1 IRON MOUNTAIN CMN 46284V101 0 -22,091 -100.00 0 -100.00
2018-05-14 2018-03-31 13F/A-1 IRON MOUNTAIN CMN 46284V101 22,091 4,051 22.46 724 6.31 0.0012
2018-05-14 2018-03-31 13F IRON MOUNTAIN CMN 46284V101 40,131 1,405
2018-02-14 2017-12-31 13F IRON MOUNTAIN CMN 46284V101 18,040 4,585 34.08 681 30.21 0.0012
2017-11-14 2017-09-30 13F IRON MOUNTAIN CMN 46284V101 13,455 -5,135 -27.62 523 -18.15 0.0011
2017-08-15 2017-06-30 13F IRON MOUNTAIN CMN 46284V101 18,590 18,590 38.16 639 22.18 0.0016
2017-05-18 2017-03-31 13F/A-1 IRON MOUNTAIN CMN 46284V101 0 -13,490 -100.00 0 -100.00
2017-02-13 2016-12-31 13F IRON MOUNTAIN CMN 46284V101 13,490 13,490 0.00 438 0.0011
2016-05-16 2016-03-31 13F IRON MOUNTAIN CMN 46284V101 0 -23,000 -100.00 0 -100.00
2016-02-12 2015-12-31 13F IRON MOUNTAIN CMN 46284V101 23,000 23,000 0.00 623 0.0017
2015-11-16 2015-09-30 13F IRON MOUNTAIN CMN 46284V101 0 -32,235 -100.00 0 -100.00
2015-08-14 2015-06-30 13F IRON MOUNTAIN CMN 46284V101 32,235 32,235 1,015 0.0029
2015-02-17 2014-12-31 13F IRON MOUNTAIN CMN 462846106 0 -253,021 -100.00 0 -100.00
2014-11-14 2014-09-30 13F IRON MOUNTAIN CMN 462846106 253,021 -486,724 -65.80 8,231 -68.31 0.0223
2014-08-13 2014-06-30 13F IRON MOUNTAIN CMN 462846106 739,745 535,698 262.54 25,975 362.35 0.0074
2014-05-14 2014-03-31 13F IRON MOUNTAIN CMN 462846106 204,047 194,153 1,962.33 5,618 1,772.67 0.0017
2014-02-14 2013-12-31 13F IRON MOUNTAIN CMN 462846106 9,894 -30,649 -75.60 300 -72.60 0.0014
2013-11-14 2013-09-30 13F IRON MOUNTAIN CMN 462846106 40,543 -18,095 -30.86 1,095 -29.90 0.0066
2013-08-15 2013-06-30 13F IRON MOUNTAIN CMN 462846106 58,638 16,800 40.15 1,562 3.03 0.0127
2013-08-16 2013-03-31 13F/A-2 IRON MOUNTAIN CMN 462846106 41,838 25,595 157.58 1,516 201.39 0.0160
2013-08-16 2012-12-31 13F/A-1 IRON MOUNTAIN CMN 462846106 16,243 16,243 503 0.0056
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2016-05-16 2016-03-31 13F IRON MOUNTAIN CMN Call 0 -100.00 0 -100.00 n/a n/a n/a
2016-02-12 2015-12-31 13F IRON MOUNTAIN CMN Call 2,100 57 n/a n/a n/a
2015-02-17 2014-12-31 13F IRON MOUNTAIN CMN Call 0 -100.00 0 -100.00 n/a n/a n/a
2014-11-14 2014-09-30 13F IRON MOUNTAIN CMN Call 515,000 -25.67 16,753 -31.14 n/a n/a n/a
2014-08-13 2014-06-30 13F IRON MOUNTAIN CMN Call 692,900 -12.82 24,330 11.16 n/a n/a n/a
2014-05-14 2014-03-31 13F IRON MOUNTAIN CMN Call 794,800 21,887 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2016-05-16 2016-03-31 13F IRON MOUNTAIN CMN Put 0 -100.00 0 -100.00 n/a n/a n/a
2016-02-12 2015-12-31 13F IRON MOUNTAIN CMN Put 11,800 319 n/a n/a n/a
2015-02-17 2014-12-31 13F IRON MOUNTAIN CMN Put 0 -100.00 0 -100.00 n/a n/a n/a
2014-11-14 2014-09-30 13F IRON MOUNTAIN CMN Put 210,000 -52.46 6,831 -55.96 n/a n/a n/a
2014-08-13 2014-06-30 13F IRON MOUNTAIN CMN Put 441,700 3,952.29 15,510 5,070.00 n/a n/a n/a
2014-05-14 2014-03-31 13F IRON MOUNTAIN CMN Put 10,900 300 n/a n/a n/a
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.