William Blair & Company
IRM icon

William Blair & Company’s Iron Mountain IRM Stock Holding History

William Blair & Company’s Portfolio IRM Stock Details IRM Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2017
Q1 		– Sell
-100
Closed -$3K – 1483
2016
Q4 		$3K Buy
+100
New +$3.32K ﹤0.01% 1390

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VPM
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VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
Cohen & Steers
Cohen & Steers New York $57.6B AUM 8.03% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
Morgan Stanley
Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return
Principal Financial Group
Principal Financial Group Des Moines, Iowa $187B AUM 18.48% 1-Year Est. Return
Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $481B AUM 30.42% 1-Year Est. Return

William Blair & Company's IRM Position: Q1 2026 in Review

William Blair & Company reduced its Iron Mountain (IRM) stake by 5.5% in Q1 2026, selling an estimated $1.3M and leaving 225,249 shares worth $23M. The position accounts for 0.07% of the portfolio, ranked #227.

William Blair & Company first reported a position in IRM in Q2 2013 and has held it in 52 quarters since. The position peaked at $39.7M in Q3 2024. 1,084 funds tracked by Wall St. Rank hold IRM as of Q1 2026.

  • William Blair & Company held 225,249 shares of Iron Mountain worth $23M as of Q1 2026.
  • William Blair & Company sold 13,036 Iron Mountain shares in Q1 2026, an estimated $1.3M.
  • Iron Mountain made up 0.07% of William Blair & Company's portfolio in Q1 2026, its #227 holding.
  • William Blair & Company first reported a position in Iron Mountain in Q2 2013 and has held it in 52 quarters since.
  • William Blair & Company's Iron Mountain position peaked at $39.7M in Q3 2024.
  • 1,084 funds tracked by Wall St. Rank held Iron Mountain as of Q1 2026.

Based on William Blair & Company's 13F filing for Q1 2026, filed 8 May 2026.