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IRM in the 13F filings

Iron MTN Inc Del · CUSIP 46284V101

Sector · Real estateTheme · Real estate investment trusts
Quarter
Q2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023Q3 2023
Quarter end
31 Dec 2025
the date the book describes
Filed
27 Oct 2026
latest of these filings; the earliest 10 Feb 2026
Managers listing it
24
at least, of 95 tracked, among listed positions
Comparable managers
92
filed both Q3 2025 and Q4 2025; 5 listed it in both
Shares listed
20,871,273
combined, among listed positions
Reported value
$1.7bn
combined, at the quarter end

Among the 92 comparable managers: 16 buyers (opened or added shares) and 10 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was +901,425.

Managers listing IRM in Q4 2025

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q3 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

24 of 24 holders

ActionFiling
Fidelity (FMR LLC)7,984,304$662munder 0.1%Added+126,21217 Feb 2026 (the filing on sec.gov)
Invesco Ltd4,417,367$366munder 0.1%Trimmed-649,14919 Feb 2026 (the filing on sec.gov)
Capital World Investors2,117,169$176munder 0.1%Held011 Feb 2026 (the filing on sec.gov)
Citadel Advisors LLC1,119,371$93munder 0.1%Added+1,058,08017 Feb 2026 (the filing on sec.gov)
AQR Capital Management LLC923,196$77munder 0.1%Added+465,72417 Feb 2026 (the filing on sec.gov)
Point72 Asset Management LP790,504$66m0.07%Trimmed-506,02717 Feb 2026 (the filing on sec.gov)
T. Rowe Price Associates Inc606,859$50munder 0.1%Added+11,26417 Feb 2026 (the filing on sec.gov)
AllianceBernstein LP544,810$45munder 0.1%Trimmed-11,18417 Feb 2026 (the filing on sec.gov)
Millennium Management LLC489,014$41munder 0.1%Added+3,59717 Feb 2026 (the filing on sec.gov)
Neuberger Berman Group LLC431,386$36munder 0.1%Added+15,13827 Oct 2026 (the filing on sec.gov)
Two Sigma Investments LP290,160$24munder 0.1%Newnew17 Feb 2026 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC209,300$17m0.08%Added+111,07117 Feb 2026 (the filing on sec.gov)
Verition Fund Management LLC208,951$17m0.07%Added+181,05113 Feb 2026 (the filing on sec.gov)
Balyasny Asset Management LLC206,809$17munder 0.1%Added+57,88017 Feb 2026 (the filing on sec.gov)
Two Sigma Advisers LP130,324$11munder 0.1%Added+123,82417 Feb 2026 (the filing on sec.gov)
Wellington Management Group LLP104,127$8.6munder 0.1%Trimmed-144,76517 Feb 2026 (the filing on sec.gov)
Susquehanna International Group LLP82,195$6.8munder 0.1%Added+14,95217 Feb 2026 (the filing on sec.gov)
Man Group PLC57,346$4.8munder 0.1%Added+45,19517 Feb 2026 (the filing on sec.gov)
Woodline Partners LP50,353$4.2munder 0.1%Added+11,39517 Feb 2026 (the filing on sec.gov)
Squarepoint Ops LLC38,822$3.2munder 0.1%Trimmed-31,50713 Feb 2026 (the filing on sec.gov)
Janus Henderson Group Ltd38,032$3.2munder 0.1%Added+58817 Feb 2026 (the filing on sec.gov)
Tudor Investment Corp22,190$1.8munder 0.1%Newnew17 Feb 2026 (the filing on sec.gov)
D. E. Shaw & Co.5,756$477kunder 0.1%Trimmed-138,28317 Feb 2026 (the filing on sec.gov)
Acadian Asset Management LLC2,928$242kunder 0.1%Trimmed-59,48810 Feb 2026 (the filing on sec.gov)

Largest increases and reductions, by shares

Q3 2025 to Q4 2025, among managers that listed it in both quarters or opened it.

Increases

Reductions

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (2)

Exited (3)

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.
6 in Q3 2024 to 6 in Q2 2026

Tracked managers listing it, at least.

051015201620182020202220242026
the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.
IRM by quarter
QuarterHoldersReported valueBuyersSellers
Q1 20154$1.2bnn.a.n.a.
Q2 20156$1.1bnn.a.n.a.
Q3 20154$1.3bnn.a.n.a.
Q4 20156$1.1bnn.a.n.a.
Q1 20164$1.4bnn.a.n.a.
Q2 20166$1.2bnn.a.n.a.
Q3 20164$1.1bnn.a.n.a.
Q4 20162$885mn.a.n.a.
Q1 20175$1.4bnn.a.n.a.
Q2 20175$1.3bnn.a.n.a.
Q3 20176$1.5bnn.a.n.a.
Q4 20176$1.3bnn.a.n.a.
Q1 20186$1.2bnn.a.n.a.
Q2 20183$1.3bnn.a.n.a.
Q3 20186$1.3bnn.a.n.a.
Q4 20184$1.3bnn.a.n.a.
Q1 201912$1.6bnn.a.n.a.
Q2 20196$1.3bnn.a.n.a.
Q3 20198$1.4bnn.a.n.a.
Q4 20195$1.2bnn.a.n.a.
Q1 20207$975mn.a.n.a.
Q2 20202$920mn.a.n.a.
Q3 20203$951mn.a.n.a.
Q4 20203$865mn.a.n.a.
Q1 20212$1.2bnn.a.n.a.
Q2 20212$1.4bnn.a.n.a.
Q3 20212$1.4bnn.a.n.a.
Q4 20213$2.0bnn.a.n.a.
Q1 20222$1.7bnn.a.n.a.
Q2 20223$1.4bnn.a.n.a.
Q3 20225$1.3bnn.a.n.a.
Q4 20225$1.6bnn.a.n.a.
Q1 20233$1.4bnn.a.n.a.
Q2 20234$1.2bnn.a.n.a.
Q3 20237$1.6bnn.a.n.a.
Q4 20239$892m63
Q1 202410$758m55
Q2 20246$811m35
Q3 20246$956m33
Q4 202410$856m63
Q1 202511$1.1bn65
Q2 202511$1.8bn55
Q3 20256$1.7bn41
Q4 20256$1.3bn1610
Q1 20269$1.7bn1614
Q2 20266$2.0bn1317

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

IRM and WELL →IRM and EQIX →IRM and PLD →Choose a stock to compare with IRM →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own IRM, latest filings →Back to the 13F Explorer →