There is a long list of 892 institutional holders of Iron Mountain within the last two holding periods in our database of 13F filers, so we've sorted through to present to you just the top 50 institutional holders of Iron Mountain by largest to smallest position reported in the institutional investor's latest 13F filing. In the institutional-holders-of-Iron Mountain table below, the initial column indicates the name of each top institutional holder of Iron Mountain, with a link to that fund's top holdings. The next columns indicate the amount of Iron Mountain stock held by each of the institutional holders of Iron Mountain, followed by the Iron Mountain position size held by the institution, and finally the date of the quarterly 13F filing period the holdings data represents for that institution.

Holder	Amount	Position Size ($ in 1000's)	As of
Vanguard Group Inc.	46,275,110	$3,238,332	12/31/2023
IRM	46,275,110	$3,238,332	12/31/2023
BlackRock Inc.	23,272,793	$1,628,630	12/31/2023
IRM	23,272,793	$1,628,630	12/31/2023
Cohen & Steers Inc.	22,475,614	$1,572,936	12/31/2023
IRM	22,475,614	$1,572,936	12/31/2023
State Street Corp	13,792,936	$973,916	12/31/2023
IRM	13,792,936	$973,916	12/31/2023
Geode Capital Management LLC	7,064,776	$493,198	12/31/2023
IRM	7,064,776	$493,198	12/31/2023
Deutsche Bank AG	4,679,209	$327,451	12/31/2023
IRM	4,679,209	$327,451	12/31/2023
Dimensional Fund Advisors LP	4,288,399	$300,106	12/31/2023
IRM	4,288,399	$300,106	12/31/2023
Capital World Investors	4,117,079	$288,113	12/31/2023
IRM	4,117,079	$288,113	12/31/2023
Daiwa Securities Group Inc.	4,086,316	$285,960	12/31/2023
IRM	4,086,316	$285,960	12/31/2023
Morgan Stanley	3,685,807	$257,933	12/31/2023
IRM	3,685,807	$257,933	12/31/2023
FMR LLC	3,522,885	$246,531	12/31/2023
IRM	3,522,885	$246,531	12/31/2023
Invesco Ltd.	3,420,229	$239,348	12/31/2023
IRM	3,420,229	$239,348	12/31/2023
Pictet Asset Management Holding SA	3,385,796	$236,938	12/31/2023
IRM	3,385,796	$236,938	12/31/2023
Norges Bank	3,263,663	$228,391	12/31/2023
IRM	3,263,663	$228,391	12/31/2023
Charles Schwab Investment Management Inc.	3,157,681	$220,975	12/31/2023
IRM	3,157,681	$220,975	12/31/2023
Northern Trust Corp	3,130,305	$219,059	12/31/2023
IRM	3,130,305	$219,059	12/31/2023
Wellington Management Group LLP	2,928,630	$204,946	12/31/2023
IRM	2,928,630	$204,946	12/31/2023
Legal & General Group Plc	2,596,065	$181,673	12/31/2023
IRM	2,596,065	$181,673	12/31/2023
Bank of New York Mellon Corp	2,119,675	$170,019	03/31/2024
IRM	2,119,675	$170,019	03/31/2024
Amundi	2,440,530	$163,857	12/31/2023
IRM	2,440,530	$163,857	12/31/2023
Prudential Financial Inc.	2,229,535	$155,718	12/31/2023
IRM	2,229,535	$155,718	12/31/2023
JPMorgan Chase & Co.	2,095,253	$146,626	12/31/2023
IRM	2,095,253	$146,626	12/31/2023
Russell Investments Group Ltd.	2,081,786	$145,879	12/31/2023
IRM	2,081,786	$145,879	12/31/2023
Citadel Advisors LLC		$141,391	12/31/2023
IRM	1,982,852	$138,760	12/31/2023
Call	231,900	$16,228	12/31/2023
Put	194,300	$13,597	12/31/2023
Epoch Investment Partners Inc.	1,976,823	$138,338	12/31/2023
IRM	1,976,823	$138,338	12/31/2023
UBS Asset Management Americas Inc.	1,631,123	$114,146	12/31/2023
IRM	1,631,123	$114,146	12/31/2023
Ameriprise Financial Inc.	1,595,666	$112,318	12/31/2023
IRM	1,595,666	$112,318	12/31/2023
DekaBank Deutsche Girozentrale	1,126,012	$90,811	03/31/2024
IRM	1,126,012	$90,811	03/31/2024
Bank of America Corp DE	1,147,798	$80,323	12/31/2023
IRM	1,147,798	$80,323	12/31/2023
Sumitomo Mitsui Trust Holdings Inc.	956,189	$76,696	03/31/2024
IRM	956,189	$76,696	03/31/2024
CIBC Private Wealth Group LLC	1,078,601	$75,480	12/31/2023
IRM	1,078,601	$75,480	12/31/2023
AGF Management Ltd.	990,998	$69,350	12/31/2023
IRM	990,998	$69,350	12/31/2023
Canada Pension Plan Investment Board	946,990	$66,270	12/31/2023
IRM	946,990	$66,270	12/31/2023
Goldman Sachs Group Inc.	940,090	$65,787	12/31/2023
IRM	940,090	$65,787	12/31/2023
Swiss National Bank	912,561	$63,861	12/31/2023
IRM	912,561	$63,861	12/31/2023
Sei Investments Co.	875,092	$61,239	12/31/2023
IRM	875,092	$61,239	12/31/2023
Captrust Financial Advisors	825,069	$57,738	12/31/2023
IRM	825,069	$57,738	12/31/2023
UBS Group AG	824,245	$57,681	12/31/2023
IRM	824,245	$57,681	12/31/2023
Nuveen Asset Management LLC	790,331	$55,369	12/31/2023
IRM	790,331	$55,369	12/31/2023
Rockefeller Capital Management L.P.	781,851	$54,714	12/31/2023
IRM	781,851	$54,714	12/31/2023
Barclays PLC	772,320	$54,049	12/31/2023
IRM	772,320	$54,049	12/31/2023
Welch & Forbes LLC	731,578	$51,196	12/31/2023
IRM	731,578	$51,196	12/31/2023
American Century Companies Inc.	729,084	$51,021	12/31/2023
IRM	729,084	$51,021	12/31/2023
Wells Fargo & Company MN		$45,761	12/31/2023
IRM	654,922	$45,831	12/31/2023
Put	1,000	$70	12/31/2023
Border to Coast Pensions Partnership Ltd	561,040	$44,967	03/31/2024
IRM	561,040	$44,967	03/31/2024
Heitman Real Estate Securities LLC	642,471	$44,960	12/31/2023
IRM	642,471	$44,960	12/31/2023
Point72 Asset Management L.P.	639,050	$44,721	12/31/2023
IRM	639,050	$44,721	12/31/2023
Neuberger Berman Group LLC	638,028	$44,649	12/31/2023
IRM	638,028	$44,649	12/31/2023
Rhumbline Advisers	637,073	$44,582	12/31/2023
IRM	637,073	$44,582	12/31/2023
Voloridge Investment Management LLC	621,230	$43,474	12/31/2023
IRM	621,230	$43,474	12/31/2023