William Blair & Company
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William Blair & Company’s Interactive Brokers IBKR Stock Holding History

William Blair & Company’s Portfolio IBKR Stock Details IBKR Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$298K Buy
4,449
+193
+5% +$13.8K ﹤0.01% 1341
2025
Q4 		$274K Sell
4,256
-148
-3% -$9.91K ﹤0.01% 1344
2025
Q3 		$303K Buy
4,404
+339
+8% +$21.3K ﹤0.01% 1302
2025
Q2 		$225K Buy
+4,065
New +$193K ﹤0.01% 1372

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BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
CCM
Cantillon Capital Management New York $665M AUM 25.91% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
Kayne Anderson Rudnick Investment Management
Kayne Anderson Rudnick Investment Management Los Angeles, California $34B AUM 6.31% 1-Year Est. Return
GWM
Greenwich Wealth Management Greenwich, Connecticut $2.45B AUM 39.53% 1-Year Est. Return
Wellington Management Group
Wellington Management Group Boston, Massachusetts $535B AUM 26.23% 1-Year Est. Return

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

William Blair & Company increased its Interactive Brokers (IBKR) stake by 4.5% in Q1 2026, buying an estimated $13.8K and bringing the position to 4,449 shares worth $298K. The position accounts for ﹤0.01% of the portfolio, ranked #1341.

William Blair & Company first reported a position in IBKR in Q2 2025 and has held it in 4 quarters since. The position peaked at $303K in Q3 2025. 996 funds tracked by Wall St. Rank hold IBKR as of Q1 2026.

  • William Blair & Company held 4,449 shares of Interactive Brokers worth $298K as of Q1 2026.
  • William Blair & Company bought 193 Interactive Brokers shares in Q1 2026, an estimated $13.8K.
  • Interactive Brokers made up ﹤0.01% of William Blair & Company's portfolio in Q1 2026, its #1341 holding.
  • William Blair & Company first reported a position in Interactive Brokers in Q2 2025 and has held it in 4 quarters since.
  • William Blair & Company's Interactive Brokers position peaked at $303K in Q3 2025.
  • 996 funds tracked by Wall St. Rank held Interactive Brokers as of Q1 2026.

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