Iron Mountain Ownership | Who Owns Iron Mountain?

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Iron Mountain Ownership Summary

Iron Mountain is owned by 84.02% institutional investors, 0.79% insiders, and 15.19% retail investors. Vanguard group is the largest institutional shareholder, holding 15.87% of IRM shares. Vanguard Real Estate Index Investor is the top mutual fund, with 3.70% of its assets in Iron Mountain shares.

IRM Ownership Benchmark

Type	Name	% Inst	% Insiders	% Retail
Stock	Iron Mountain	84.02%	0.79%	15.19%
Sector	Real Estate Stocks	70.14%	9.14%	20.72%
Industry	Specialty REIT Stocks	85.67%	3.51%	10.82%

Institutional Shareholders

Top Institutional Shareholders by Total Shares

Holder	Shares	% Holding	Value
Vanguard group	46.61M	15.87%	$4.90B
Blackrock funding, inc. /de	31.28M	10.59%	$3.21B
Blackrock	27.89M	9.53%	$2.50B
State street	17.52M	5.98%	$1.58B
Cohen & steers	13.77M	4.66%	$1.41B
Geode capital management	7.91M	2.69%	$832.88M
Dimensional fund advisors lp	4.22M	1.44%	$443.48M
Morgan stanley	3.66M	1.25%	$327.60M
Charles schwab investment management	3.48M	1.18%	$365.66M
Norges bank	3.31M	1.13%	$348.25M

Top Institutional Shareholders by % of Total Assets

Holder	Shares	% Assets	Value
Contour asset management	2.34M	7.83%	$239.54M
Waterfront capital partners	210.47K	5.29%	$21.59M
Vert asset management	129.48K	4.84%	$13.28M
Foresight capital management advisors	82.05K	4.70%	$8.36M
Marble harbor investment counsel	328.77K	3.67%	$33.72M
Heitman real estate securities	463.52K	3.37%	$47.54M
Aew capital management l p	619.68K	3.35%	$63.56M
Adelante capital management	403.20K	3.04%	$41.36M
Ar asset management	130.60K	2.98%	$13.40M
Gillson capital lp	369.14K	2.89%	$37.86M

Top Buyers

Holder	Shares	% Assets	Change
Blackrock	27.89M	0.06%	4.78M
State street	17.52M	0.07%	3.70M
Norges bank	3.31M	0.05%	3.31M
Td asset management	1.95M	0.18%	1.09M
Vontobel	1.08M	0.33%	1.08M

Top Sellers

Holder	Shares	% Assets	Change
Blackrock funding, inc. /de	31.28M	0.06%	-3.94M
Ubs asset management americas	426.22K	0.01%	-2.74M
Agf management	-	-	-2.13M
Citadel advisors	-	-	-1.27M
Point72 asset management	1.01M	0.20%	-1.06M

New Positions

Holder	Shares	% Assets	Change	Value
Norges bank	3.31M	0.05%	3.31M	$348.25M
Zurich insurance group ltd/fi	513.79K	0.41%	513.79K	$52.70M
Gillson capital lp	369.14K	2.89%	369.14K	$37.86M
Intrinsic edge capital management	184.84K	2.65%	184.84K	$18.96M
Caption management	136.20K	0.19%	136.20K	$12.21M

Sold Out

Holder	Change
Quest partners	-1.00
Financial gravity asset management	-1.00
Cape investment advisory	-1.00
Mendota financial group	-1.00
Westend advisors	-2.00

Institutional Ownership Trends

Date	Holdings	Change %	Shares	Change %	Ownership	Change %	Increased Position	Change %	Decreased Position	Change %
Jun 30, 2025	1,058	4.65%	248,166,621	3.56%	84	1.27%	506	18.50%	353	-11.75%
Mar 31, 2025	996	-8.03%	240,406,567	1.52%	81	1.25%	417	-13.13%	397	-3.64%
Dec 31, 2024	781	-27.82%	190,161,466	-20.39%	64	0.98%	327	-31.30%	315	-24.82%
Sep 30, 2024	1,072	8.83%	238,410,694	-3.76%	81	1.14%	475	9.20%	411	11.08%
Jun 30, 2024	970	1.04%	247,508,042	5.77%	84	1.32%	428	-1.15%	368	10.84%

Top Mutual Funds Shareholders

Holder	Shares	% Holding	Change
Vanguard Real Estate Index Investor	10.91M	3.70%	12.83K
Vanguard US Total Market Shares ETF	9.29M	3.16%	12.82K
Vanguard Total Stock Mkt Idx Inv	9.27M	3.14%	-219.41K
Vanguard Institutional 500 Index Trust	8.35M	2.83%	58.03K
Vanguard 500 Index Investor	7.30M	2.47%	-1.07M
Vanguard Mid Cap Index Institutional	6.58M	2.23%	70.93K
Fidelity 500 Index	3.74M	1.27%	1.60K
SPDR® S&P 500 ETF	3.56M	1.21%	-144.37K
SPDR® S&P 500® ETF Trust	3.56M	1.21%	-18.68K
SPDR® S&P 500® ETF	3.57M	1.21%	43.77K

Recent Insider Transactions

Date	Name	Role	Activity	Value
Oct 01, 2025	Meaney William L	President and CEO	Sell	$2.96M
Oct 01, 2025	Meaney William L	President and CEO	Sell	$4.11M
Oct 01, 2025	Kidd Mark	EVP, GM Data Centers & ALM	Sell	$609.78K
Sep 03, 2025	Meaney William L	President and CEO	Sell	$6.19M
Sep 02, 2025	Kidd Mark	EVP, GM Data Centers & ALM	Sell	$546.30K

Insider Transactions Trends

Date	Buy	Sell
2025 Q4	-	3
2025 Q3	-	13
2025 Q2	-	13
2025 Q1	-	21
2024 Q4	-	7

IRM Ownership FAQ

Who Owns Iron Mountain?

Iron Mountain shareholders are primarily institutional investors at 84.02%, followed by 0.79% insiders and 15.19% retail investors. The average institutional ownership in Iron Mountain's industry, Specialty REIT Stocks , is 85.67%, which Iron Mountain falls below.

Who owns the most shares of Iron Mountain?

Iron Mountain’s largest shareholders are Vanguard group (46.61M shares, 15.87%), Blackrock funding, inc. /de (31.28M shares, 10.59%), and Blackrock (27.89M shares, 9.53%). Together, they hold 35.99% of Iron Mountain’s total shares outstanding.

Does Blackrock own Iron Mountain?

Yes, BlackRock owns 9.53% of Iron Mountain, totaling 27.89M shares as of Jun 2024. This represents 0.06% of BlackRock's total assets, with a market value of 2.5B$. In the last quarter, BlackRock increased its holdings by 4.78M shares, a 20.70% change.

Who is Iron Mountain’s biggest shareholder by percentage of total assets invested?

Contour asset management is Iron Mountain’s biggest shareholder by percentage of total assets invested, with 7.83% of its assets in 2.34M Iron Mountain shares, valued at 239.54M$.

Who is the top mutual fund holder of Iron Mountain shares?

Vanguard Real Estate Index Investor is the top mutual fund holder of Iron Mountain shares, with 3.70% of its total shares outstanding invested in 10.91M Iron Mountain shares.

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