Iron Mountain IRM Institutional Ownership

NYSE IRM

$115.12 +2.20 (+1.95%)

At close: Sep 11, 2026 · 4:00 PM EDT

Institutions by Trading Activity

1,158 Institutions

Increased 593 51.2%

Unchanged 185 16.0%

Reduced 380 32.8%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

87.61%

▲+2.77 pp QoQ

Shares Held by Institutions

260.86Mn

of 297.74Mn outstanding

▲+4.49% QoQ

Shares Outstanding

297.74Mn

36.88Mn held outside 13F filers

Institutional Investors

1,158

filed 13F for Jun 2026

▲+80 vs prior quarter

Net Shares Added (QoQ)

+11.20Mn

accumulated since last quarter

Value of Holdings

$30.03Bn

reported market value

Shares Owned by Institutions

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Institutions

Accumulated Distributed

Latest quarter —

Net over range —

Accumulating quarters —

Ownership Summary

Quarter ending 30 Jun, 2026

Iron Mountain Inc (NYSE:IRM) is held by 1,158 institutional investors per 13F filings through June 2026.

These investors collectively held 87.6% of Iron Mountain's outstanding shares in June 2026, up from 84.8% in March 2026.
Their total shares held in IRM increased 4.49% quarter over quarter, and separately, investors owning Iron Mountain increased 11.67% from a year ago.
Of these 1,158 holders, 593 added to their stakes in Iron Mountain, 380 trimmed positions, and 185 made no changes.
Altogether, these fund groups held 260.86Mn shares in IRM by June 2026, up by 11.2Mn shares quarter on quarter, and up 10.89Mn shares year over year.
BlackRock, Inc. holds the largest position in IRM at 33.57Mn shares as of June 30, 2026, or 11.28% of shares outstanding.
The biggest buyers of Iron Mountain for the quarter ending June 2026 included Sixth Street Partners Management Company, L.P. (4.26Mn), NORGES BANK (4.21Mn), UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC (3.18Mn), CBRE INVESTMENT MANAGEMENT LISTED REAL ASSETS LLC (1.07Mn), Goldman Sachs Group Inc (606.06K).
The largest sellers of Iron Mountain for the quarter ending June 2026 were Cohen & Steers, Inc. (4.15Mn), Daiwa Securities Group Inc. (1.25Mn), PGGM Investments (694.9K), Capital World Investors (650.0K), Prudential Financial Inc (441.98K).
According to Business Quant data, leading holders of IRM for June 2026 are BlackRock, Inc. (33.57Mn), VANGUARD PORTFOLIO MANAGEMENT LLC (25.57Mn), VANGUARD CAPITAL MANAGEMENT LLC (18.95Mn), State Street Corp (17.63Mn), Cohen & Steers, Inc. (12.02Mn), GEODE CAPITAL MANAGEMENT, LLC (8.65Mn), FMR LLC (7.87Mn), DIMENSIONAL FUND ADVISORS LP (4.63Mn), Morgan Stanley (4.43Mn), Principal Financial Group Inc (4.37Mn).

Form 13F Holdings

1,158 Institutional Holders

Report period 30 Jun, 2026

Total shares held 260.86Mn

Of outstanding 87.61%

#	Institution	CIK	Shares Held	% of Outstanding	Change (QoQ)	Change (%)	Value (USD)
1	BlackRock, Inc.	0002012383	33,570,910	11.28%	▲549,556	+1.66%	$4.24Bn
2	VANGUARD PORTFOLIO MANAGEMENT LLC	0002100121	25,568,944	8.59%	▲553,387	+2.21%	$3.23Bn
3	VANGUARD CAPITAL MANAGEMENT LLC	0002100119	18,953,705	6.37%	▲194,816	+1.04%	$2.39Bn
4	State Street Corp	0000093751	17,634,044	5.92%	▲82,411	+0.47%	$2.24Bn
5	Cohen & Steers, Inc.	0001284812	12,019,735	4.04%	▼4,149,606	-25.66%	$1.52Mn
6	GEODE CAPITAL MANAGEMENT, LLC	0001214717	8,649,249	2.90%	▲163,122	+1.92%	$1.09Bn
7	FMR LLC	0000315066	7,872,365	2.64%	▲387,967	+5.18%	$994.36Mn
8	DIMENSIONAL FUND ADVISORS LP	0000354204	4,625,684	1.55%	▲73,398	+1.61%	$584.31Mn
9	Morgan Stanley	0000895421	4,426,922	1.49%	▼225,325	-4.84%	$559.16Mn
10	Principal Financial Group Inc	0001126328	4,373,424	1.47%	▼192,669	-4.22%	$552.40Mn
11	CHARLES SCHWAB INVESTMENT MANAGEMENT INC	0000884546	4,263,487	1.43%	▲250,480	+6.24%	$538.52Mn
11	Sixth Street Partners Management Company, L.P.	0001812095	4,263,487	1.43%	▲4,263,487	0.00%	$538.52Mn
12	Northern Trust Corp	0000073124	4,222,967	1.42%	▲72,481	+1.75%	$533.40Mn
13	NORGES BANK	0001374170	4,214,697	1.42%	▲4,214,697	0.00%	$532.36Mn
14	Invesco Ltd.	0000914208	4,065,649	1.37%	▲144,128	+3.68%	$513.53Mn
15	Legal & General Group Plc	0000764068	3,244,741	1.09%	▲109,667	+3.50%	$409.84Mn
16	UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC	0000861177	3,193,560	1.07%	▲3,182,834	+29,674.01%	$403.38Mn
17	DEUTSCHE BANK AG\	0000948046	3,049,079	1.02%	▼43,005	-1.39%	$385.13Mn
18	Goldman Sachs Group Inc	0000886982	2,822,732	0.95%	▲606,060	+27.34%	$356.54Mn
19	CENTERSQUARE INVESTMENT MANAGEMENT LLC	0001725296	2,323,974	0.78%	▲13,929	+0.60%	$293.54Mn

Showing 1 to 20 of 1,158 holders