Iron Mountain Incorporated
US ˙ NYSE ˙ US46284V1017

SecurityIRM / Iron Mountain Incorporated
InstitutionAdvisor Group Holdings, Inc.
Latest Disclosed Ownership110,503 shares
Latest Disclosed Value $ 11,293,355
Advisor Group Holdings, Inc. ownership in IRM / Iron Mountain Incorporated

On May 15, 2026 - Advisor Group Holdings, Inc. filed a 13F-HR form disclosing ownership of 110,503 shares of Iron Mountain Incorporated (US:IRM) valued at $11,286,776 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 123,416 shares of Iron Mountain Incorporated. This represents a change in shares of -10.46% during the quarter. The current value of the position is $14,138,859 USD.

Advisor Group Holdings, Inc. has a history of taking positions in derivatives of the underlying security (IRM) in the form of stock options.

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.

IRM / 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 110,503 -12,913 -10.46 11,293 10.27 0.0096
2026-02-17 2025-12-31 13F IRON MTN INC DEL COM 46284V101 123,416 -31,201 -20.18 10,242 -32.25 0.0150
2025-11-14 2025-09-30 13F IRON MTN INC DEL COM 46284V101 154,617 35,470 29.77 15,115 23.73 0.0212
2025-09-04 2025-06-30 13F/A-1 RON MTN INC DEL COM 46284V101 119,147 -2,005 -1.65 12,216 17.17 0.0217
2025-08-13 2025-06-30 13F RON MTN INC DEL COM 46284V101 85,475 -35,677 8,946 0.0103
2025-05-12 2025-03-31 13F IRON MTN INC DEL COM 46284V101 121,152 6,930 6.07 10,427 -13.17 0.0232
2025-06-06 2024-12-31 13F/A-1 IRON MTN INC DEL COM 46284V101 114,222 -1,253 -1.09 12,008 -12.50 0.0270
2025-02-07 2024-12-31 13F IRON MTN INC DEL COM 46284V101 108,971 -6,504 12,396 0.0316
2024-11-13 2024-09-30 13F IRON MTN INC DEL COM 46284V101 115,475 -2,966 -2.50 13,724 29.27 0.0309
2024-08-13 2024-06-30 13F IRON MTN INC DEL COM 46284V101 118,441 -13,100 -9.96 10,617 0.61 0.0251
2024-05-10 2024-03-31 13F IRON MTN INC DEL COM 46284V101 131,541 -5,740 -4.18 10,553 9.81 0.0236
2024-02-12 2023-12-31 13F IRON MTN INC DEL COM 46284V101 137,281 -43,019 -23.86 9,609 -10.36 0.0168
2023-11-13 2023-09-30 13F IRON MTN INC DEL COM 46284V101 180,300 38,410 27.07 10,721 32.85 0.0158
2023-08-21 2023-06-30 13F/A-1 IRON MTN INC DEL COM 46284V101 141,890 -6,986 -4.69 8,069 2.45 0.0145
2023-08-10 2023-06-30 13F IRON MTN INC DEL COM 46284V101 157,520 8,644 8,053 0.0022
2023-05-12 2023-03-31 13F IRON MTN INC DEL COM 46284V101 148,876 -1,283 -0.85 7,876 5.20 0.0148
2023-02-10 2022-12-31 13F IRON MTN INC DEL COM 46284V101 150,159 -19,999 -11.75 7,487 0.07 0.0152
2022-11-14 2022-09-30 13F IRON MTN INC DEL COM 46284V101 170,158 -25,996 -13.25 7,482 -21.68 0.0171
2022-08-10 2022-06-30 13F IRON MTN INC COM 46284V101 196,154 6,029 3.17 9,553 -8.38 0.0211
2022-05-04 2022-03-31 13F IRON MTN INC COM 46284V101 190,125 16,197 9.31 10,427 14.56 0.0202
2022-02-03 2021-12-31 13F IRON MTN INC COM 46284V101 173,928 -23,632 -11.96 9,102 6.00 0.0172
2021-11-05 2021-09-30 13F IRON MTN INC COM 46284V101 197,560 21,297 12.08 8,587 15.06 0.0179
2021-08-02 2021-06-30 13F IRON MTN INC COM 46284V101 176,263 -21,771 -10.99 7,463 1.76 0.0162
2021-05-13 2021-03-31 13F IRON MTN INC COM 46284V101 198,034 -39,440 -16.61 7,334 4.76 0.0176
2021-02-10 2020-12-31 13F IRON MTN INC COM 46284V101 237,474 -46,328 -16.32 7,001 -7.93 0.0187
2020-11-12 2020-09-30 13F IRON MTN INC COM 46284V101 283,802 -45,844 -13.91 7,604 -11.64 0.0227
2020-08-14 2020-06-30 13F IRON MTN INC COM 46284V101 329,646 -848,563 -72.02 8,606 46.61 0.0289
2020-05-18 2020-03-31 13F IRON MTN INC COM 46284V101 1,178,209 1,178,209 5,870 0.0240
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
(%)
2021-05-13 2021-03-31 13F IRON MTN INC NEW PUT COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-10 2020-12-31 13F IRON MTN INC NEW PUT COM Put 7 0.00 2 -50.00 n/a n/a n/a
2020-11-12 2020-09-30 13F IRON MTN INC NEW PUT COM Put 7 0.00 4 -33.33 n/a n/a n/a
2020-08-14 2020-06-30 13F IRON MTN INC NEW PUT COM Put 7 0.00 6 0.00 n/a n/a n/a
2020-05-18 2020-03-31 13F IRON MTN INC NEW PUT COM Put 7 6 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.