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William Blair Investment Management

William Blair Investment Management Portfolio holdings

AUM $33.3B
1-Year Est. Return 44.76%
This Fund
S&P 500
This Quarter Est. Return
+3.11%
1 Year Est. Return
+44.76%
3 Year Est. Return
+140.8%
5 Year Est. Return
+166.51%
10 Year Est. Return
+978.6%
AUM
$35.9B
AUM Growth
-$2.82B
Cap. Flow
-$3B
Cap. Flow %
-8.37%
Top 10 Hldgs %
32.55%
Holding
459
New
45
Increased
106
Reduced
259
Closed
46

Top Buys

Rank Stock Value
1
SNOW icon
Snowflake
SNOW
+$202M
2
ARGX icon
argenx
ARGX
+$191M
3
GOOGL icon
Alphabet (Google) Class A
GOOGL
+$191M
4
HQY icon
HealthEquity
HQY
+$178M
5
FFIV icon
F5
FFIV
+$148M

Top Sells

Rank Stock Value
1
LRCX icon
Lam Research
LRCX
+$270M
2
CIEN icon
Ciena
CIEN
+$260M
3
UBER icon
Uber
UBER
+$233M
4
LYV icon
Live Nation Entertainment
LYV
+$229M
5
LRN icon
Stride
LRN
+$225M

Sector Composition

Rank Sector Weight
1 Technology 37.93%
2 Financials 12.94%
3 Healthcare 12.67%
4 Consumer Discretionary 10.8%
5 Industrials 9.43%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow
OMF icon
201
OneMain Financial
OMF
$7.44B
$29.7M 0.08%
439,696
-55,120
-11% -$3.35M
ULS icon
202
UL Solutions
ULS
$15.5B
$29.7M 0.08%
376,039
-26,171
-7% -$2.1M
RMBS icon
203
Rambus
RMBS
$11B
$29.1M 0.08%
316,397
+25,215
+9% +$2.48M
USPH icon
204
US Physical Therapy
USPH
$1.22B
$28.9M 0.08%
370,707
+24,848
+7% +$2.02M
KLIC icon
205
Kulicke & Soffa
KLIC
$4.98B
$28.8M 0.08%
632,017
-66,141
-9% -$2.79M
FRME icon
206
First Merchants
FRME
$2.72B
$28.6M 0.08%
763,904
-79,270
-9% -$2.94M
DBRG icon
207
DigitalBridge
DBRG
$2.95B
$28.6M 0.08%
1,865,445
-633,469
-25% -$7.61M
XPRO icon
208
Expro Ltd
XPRO
$2.07B
$28.5M 0.08%
2,135,539
-219,553
-9% -$2.96M
KNX icon
209
Knight Transportation
KNX
$11.6B
$28.5M 0.08%
544,239
+34,320
+7% +$1.61M
HAYW icon
210
Hayward Holdings
HAYW
$3.25B
$28.2M 0.08%
1,822,243
-188,497
-9% -$2.98M
SR icon
211
Spire
SR
$4.89B
$28M 0.08%
339,016
-35,034
-9% -$2.99M
ESNT icon
212
Essent Group
ESNT
$6.14B
$28M 0.08%
+430,449
New +$26.7M
BRC icon
213
Brady Corp
BRC
$4.48B
$27.6M 0.08%
352,534
-36,842
-9% -$2.85M
KFY icon
214
Korn Ferry
KFY
$4.28B
$27.4M 0.08%
414,465
+16,821
+4% +$1.13M
SHOO icon
215
Steven Madden
SHOO
$3.49B
$27.4M 0.08%
656,999
-68,450
-9% -$2.64M
THG icon
216
Hanover Insurance
THG
$7.74B
$27.3M 0.08%
149,219
+9,327
+7% +$1.68M
MMS icon
217
Maximus
MMS
$2.85B
$27.1M 0.08%
313,594
-31,716
-9% -$2.71M
TPH
218
DELISTED
Tri Pointe Homes
TPH
$27M 0.08%
857,226
-90,190
-10% -$2.93M
FBK icon
219
FB Financial Corp
FBK
$3.1B
$27M 0.08%
+483,200
New +$27M
ALK icon
220
Alaska Air
ALK
$5.29B
$26.9M 0.08%
535,121
-55,160
-9% -$2.55M
SLGN icon
221
Silgan Holdings
SLGN
$4.3B
$26.9M 0.08%
666,415
+68,611
+11% +$2.78M
ABCB icon
222
Ameris Bancorp
ABCB
$5.94B
$26.9M 0.08%
362,194
-295,337
-45% -$22M
NWN icon
223
Northwest Natural Holdings
NWN
$2.12B
$26.9M 0.08%
+575,198
New +$26.8M
LZB icon
224
La-Z-Boy
LZB
$1.64B
$26.8M 0.07%
719,246
+83,149
+13% +$2.91M
NWE icon
225
NorthWestern Energy
NWE
$4.34B
$26.7M 0.07%
413,328
-42,892
-9% -$2.72M
7 8
9
10 11

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William Blair Investment Management's Q4 2025 Portfolio in Review

As of Q4 2025, William Blair Investment Management held 459 positions worth $35.9B, down 7.3% from $38.7B the previous quarter. Its ten largest holdings account for 33% of the portfolio.

William Blair Investment Management withdrew a net $3B in Q4 2025, closing 46 positions and reducing 259 holdings. Its most notable exit was Live Nation Entertainment, an estimated $229M position sold in full.

By sector, the portfolio is most concentrated in Technology at 38% of assets, down from 39% a quarter earlier, followed by Financials and Healthcare.

Against the trend, William Blair Investment Management opened a new position in argenx worth $188M.

  • William Blair Investment Management's largest Q4 2025 buy was argenx: 223,666 shares worth $188M.
  • William Blair Investment Management added most to Snowflake in Q4 2025, an estimated $202M increase.
  • William Blair Investment Management's biggest Q4 2025 reduction was Lam Research, cutting an estimated $270M.
  • William Blair Investment Management fully exited Live Nation Entertainment in Q4 2025, selling an estimated $229M.
  • William Blair Investment Management's ten largest holdings make up 33% of its $35.9B portfolio in Q4 2025.
  • William Blair Investment Management opened 45 new positions and closed 46 in Q4 2025.
  • William Blair Investment Management's portfolio value fell 7.3% quarter-over-quarter to $35.9B.

Based on William Blair Investment Management's 13F filing for Q4 2025, filed 9 Feb 2026.