William Blair Investment Management
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William Blair Investment Management’s OSI Systems OSIS Stock Holding History

William Blair Investment Management’s Portfolio OSIS Stock Details OSIS Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$83M Buy
379,351
+207,684
+121% +$50.9M 0.25% 116
2026
Q1 		$45.6M Sell
171,667
-19,659
-10% -$5.44M 0.15% 143
2025
Q4 		$48.8M Buy
+191,326
New +$50M 0.14% 141
2017
Q3 		– Sell
-48,304
Closed -$3.63M – 451
2017
Q2 		$3.63M Sell
48,304
-69,612
-59% -$5.27M 0.01% 368
2017
Q1 		$8.61M Sell
117,916
-8,715
-7% -$647K 0.03% 318
2016
Q4 		$9.64M Buy
126,631
+22,409
+22% +$1.62M 0.04% 311
2016
Q3 		$6.81M Sell
104,222
-23,272
-18% -$1.47M 0.03% 336
2016
Q2 		$7.41M Buy
127,494
+1,365
+1% +$75.2K 0.03% 326
2016
Q1 		$8.26M Buy
126,129
+14,469
+13% +$958K 0.03% 306
2015
Q4 		$9.9M Sell
111,660
-39,935
-26% -$3.49M 0.04% 285
2015
Q3 		$11.7M Buy
+151,595
New +$10.9M 0.02% 649

Other funds holding OSIS

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
JT
Jupiter Topco New York $245B AUM
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Capital International Investors
Capital International Investors Los Angeles, California $484B AUM 34.9% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
UBS AM
UBS AM Chicago, Illinois $550B AUM 43.33% 1-Year Est. Return
CCM
Channing Capital Management Chicago, Illinois $4.34B AUM 37.08% 1-Year Est. Return

William Blair Investment Management's OSIS Position: Q2 2026 in Review

William Blair Investment Management increased its OSI Systems (OSIS) stake by 121% in Q2 2026, buying an estimated $50.9M and bringing the position to 379,351 shares worth $83M. The position accounts for 0.25% of the portfolio, ranked #116.

William Blair Investment Management first reported a position in OSIS in Q3 2015 and has held it in 11 quarters since. 362 funds tracked by Wall St. Rank hold OSIS as of Q2 2026.

  • William Blair Investment Management held 379,351 shares of OSI Systems worth $83M as of Q2 2026.
  • William Blair Investment Management bought 207,684 OSI Systems shares in Q2 2026, an estimated $50.9M.
  • OSI Systems made up 0.25% of William Blair Investment Management's portfolio in Q2 2026, its #116 holding.
  • William Blair Investment Management first reported a position in OSI Systems in Q3 2015 and has held it in 11 quarters since.
  • 362 funds tracked by Wall St. Rank held OSI Systems as of Q2 2026.

Based on William Blair Investment Management's 13F filing for Q2 2026, filed 12 Aug 2026.