Iron Mountain Inc (IRM) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

0Shares Outstanding

3,974,340Shares held by institutions

$386,743,025Value of institutional holdings

84.56%Institutional ownership %

0.72%Shares Changed QoQ

1,030No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

Iron Mountain Inc (NYSE:IRM) appears in 971 institutional 13F filings for the quarter ending December 2025.

Their combined ownership stood at 86.0% of outstanding shares in December 2025, up from 85.5% in September 2025.
Their total shares held in IRM increased 2.6% quarter over quarter, and separately, investors owning Iron Mountain decreased 6.81% from a year ago.
Of these 971 holders, 422 added to their stakes in Iron Mountain, 404 trimmed positions, and 145 made no changes.
The aggregate institutional position in Iron Mountain amounted to 256.14Mn shares as of December 2025, up by 6.48Mn shares quarter on quarter, and up 10.64Mn shares year over year.
As of December 31, 2025, the biggest holder of Iron Mountain is VANGUARD GROUP INC at 46.63Mn shares, representing 15.66% of shares outstanding.
The biggest buyers of Iron Mountain for the quarter ending December 2025 included NORGES BANK (4.45Mn), Cohen & Steers, Inc. (3.16Mn), Principal Financial Group Inc (1.68Mn), BlackRock, Inc. (1.21Mn), CITADEL ADVISORS LLC (1.06Mn).
The biggest sellers of Iron Mountain for the quarter ending December 2025 included UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC (3.16Mn), Jpmorgan Chase & Co (2.18Mn), Royal Bank Of Canada (1.01Mn), Bank Of America Corp /De/ (945.56K), Invesco Ltd. (649.15K).
Iron Mountain's 10 largest shareholders as of December 2025 include VANGUARD GROUP INC (46.63Mn), BlackRock, Inc. (32.92Mn), Cohen & Steers, Inc. (18.9Mn), State Street Corp (16.89Mn), GEODE CAPITAL MANAGEMENT, LLC (8.29Mn), FMR LLC (7.98Mn), NORGES BANK (4.45Mn), DIMENSIONAL FUND ADVISORS LP (4.43Mn), Invesco Ltd. (4.42Mn), Principal Financial Group Inc (4.21Mn) per Business Quant data.

972 Institutional Holders

3,974,340 Total Shares Held

Rows:

Download Data

Owner Name	Date	Change (QoQ)	Change (%)	Value (USD)
BlackRock, Inc.	31 Dec, 2025	1,210,594	3.82%	$0.00
VANGUARD GROUP INC	31 Dec, 2025	-625,617	-1.32%	$0.00
CENTERSQUARE INVESTMENT MANAGEMENT LLC	31 Dec, 2025	116,989	4.65%	$0.00
HSBC HOLDINGS PLC	31 Dec, 2025	1,159,974	121.90%	$0.00
Cohen & Steers, Inc.	31 Dec, 2025	3,155,034	20.03%	$0.00
Pictet Asset Management Holding SA	31 Dec, 2025	-168,203	-6.83%	$0.00
Rockefeller Capital Management L.P.	31 Dec, 2025	400,530	98.30%	$0.00
State Street Corp	31 Dec, 2025	-242,989	-1.42%	$0.00
Nuveen, LLC	31 Dec, 2025	-14,574	-0.68%	$0.00
Barclays Plc	31 Dec, 2025	-602,335	-45.25%	$0.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	102,073	1.25%	$0.00
Russell Investments Group, Ltd.	31 Dec, 2025	-300,675	-17.62%	$0.00
World Investment Advisors	31 Dec, 2025	16,566	147.99%	$0.00
FMR LLC	31 Dec, 2025	126,212	1.61%	$0.00
UBS Group AG	31 Dec, 2025	-640,393	-44.59%	$0.00
PEAK6 LLC	31 Dec, 2025	10,634	0.00%	$0.00
NORGES BANK	31 Dec, 2025	4,447,133	0.00%	$0.00
Point72 Asset Management, L.P.	31 Dec, 2025	-506,027	-39.03%	$0.00
Bank of New Hampshire	31 Dec, 2025	115	14.47%	$0.00
DIMENSIONAL FUND ADVISORS LP	31 Dec, 2025	81,320	1.87%	$0.00

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