William Blair & Company
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William Blair & Company’s Monolithic Power Systems MPWR Stock Holding History

William Blair & Company’s Portfolio MPWR Stock Details MPWR Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2014
Q4 		– Sell
-2,000
Closed -$88K – 2129
2014
Q3 		$88K Buy
+2,000
New +$88K ﹤0.01% 2028

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VCM
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VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
Invesco
Invesco Atlanta, Georgia $1.02T AUM 30.18% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
T. Rowe Price Associates
T. Rowe Price Associates Baltimore, Maryland $865B AUM 30.76% 1-Year Est. Return
Franklin Resources
Franklin Resources San Mateo, California $408B AUM 30.18% 1-Year Est. Return
T. Rowe Price Investment Management
T. Rowe Price Investment Management Baltimore, Maryland $145B AUM 22.78% 1-Year Est. Return

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

William Blair & Company increased its Monolithic Power Systems (MPWR) stake by 124% in Q1 2026, buying an estimated $18.5M and bringing the position to 30,557 shares worth $33.4M. The position accounts for 0.1% of the portfolio, ranked #181.

William Blair & Company first reported a position in MPWR in Q2 2013 and has held it in 48 quarters since. 1,114 funds tracked by Wall St. Rank hold MPWR as of Q1 2026.

  • William Blair & Company held 30,557 shares of Monolithic Power Systems worth $33.4M as of Q1 2026.
  • William Blair & Company bought 16,910 Monolithic Power Systems shares in Q1 2026, an estimated $18.5M.
  • Monolithic Power Systems made up 0.1% of William Blair & Company's portfolio in Q1 2026, its #181 holding.
  • William Blair & Company first reported a position in Monolithic Power Systems in Q2 2013 and has held it in 48 quarters since.
  • 1,114 funds tracked by Wall St. Rank held Monolithic Power Systems as of Q1 2026.

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