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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 Mar 2026
the date the book describes
Filed
27 Oct 2026
latest of these filings; the earliest 12 May 2026
Managers listing it
27
at least, of 95 tracked, among listed positions
Comparable managers
91
filed both Q4 2025 and Q1 2026; 5 listed it in both
Shares listed
20,190,227
combined, among listed positions
Reported value
$2.0bn
combined, at the quarter end

AllianceBernstein LP. Values in this filing are at the previous quarter end's prices; its share count is the quarter end's.

Among the 91 comparable managers: 16 buyers (opened or added shares) and 14 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was -550,722.

Managers listing IRM in Q1 2026

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q4 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

27 of 27 holders

ActionFiling
Fidelity (FMR LLC)7,484,398$764munder 0.1%Trimmed-499,90615 May 2026 (the filing on sec.gov)
Invesco Ltd3,921,521$401munder 0.1%Trimmed-495,84612 May 2026 (the filing on sec.gov)
Capital World Investors1,867,169$191munder 0.1%Trimmed-250,00013 May 2026 (the filing on sec.gov)
AQR Capital Management LLC1,846,073$183m0.08%Added+922,87715 May 2026 (the filing on sec.gov)
Jane Street Group LLC707,441$72munder 0.1%Newnew12 May 2026 (the filing on sec.gov)
T. Rowe Price Associates Inc601,581$61munder 0.1%Trimmed-5,27815 May 2026 (the filing on sec.gov)
AllianceBernstein LP565,255$47munder 0.1%Added+20,44515 May 2026 (the filing on sec.gov)
Point72 Asset Management LP377,618$39munder 0.1%Trimmed-412,88615 May 2026 (the filing on sec.gov)
Citadel Advisors LLC374,954$38munder 0.1%Trimmed-744,41715 May 2026 (the filing on sec.gov)
Millennium Management LLC374,463$38munder 0.1%Trimmed-114,55115 May 2026 (the filing on sec.gov)
Neuberger Berman Group LLC360,751$37munder 0.1%Trimmed-70,63527 Oct 2026 (the filing on sec.gov)
Wellington Management Group LLP347,915$36munder 0.1%Added+243,78815 May 2026 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC248,886$25m0.18%Added+39,58615 May 2026 (the filing on sec.gov)
Hudson Bay Capital Management LP190,884$19m0.07%Newnew13 May 2026 (the filing on sec.gov)
Two Sigma Investments LP179,202$18munder 0.1%Trimmed-110,95815 May 2026 (the filing on sec.gov)
Acadian Asset Management LLC168,907$17munder 0.1%Added+165,97913 May 2026 (the filing on sec.gov)
Balyasny Asset Management LLC128,692$13munder 0.1%Trimmed-78,11715 May 2026 (the filing on sec.gov)
Walleye Capital LLC119,864$12m0.05%Newnew13 May 2026 (the filing on sec.gov)
Susquehanna International Group LLP102,080$10munder 0.1%Added+19,88515 May 2026 (the filing on sec.gov)
Squarepoint Ops LLC81,640$8.3munder 0.1%Added+42,81815 May 2026 (the filing on sec.gov)
Woodline Partners LP57,860$5.9munder 0.1%Added+7,50715 May 2026 (the filing on sec.gov)
Tudor Investment Corp37,208$3.8munder 0.1%Added+15,01815 May 2026 (the filing on sec.gov)
Janus Henderson Group Ltd33,266$3.4munder 0.1%Trimmed-4,76618 May 2026 (the filing on sec.gov)
Bridgewater Associates LP4,694$479kunder 0.1%Newnew15 May 2026 (the filing on sec.gov)
Brevan Howard Capital Management LP3,272$334kunder 0.1%Newnew15 May 2026 (the filing on sec.gov)
Page 1 of 2

Largest increases and reductions, by shares

Q4 2025 to Q1 2026, 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 (7)

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 →