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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
FHN icon
76
First Horizon
FHN
$12.3B
$128M 0.36%
5,336,021
+116,191
+2% +$2.59M
GKOS icon
77
Glaukos
GKOS
$11B
$125M 0.35%
1,106,918
+13,174
+1% +$1.26M
HALO icon
78
Halozyme
HALO
$11.6B
$124M 0.35%
+1,842,956
New +$124M
CMG icon
79
Chipotle Mexican Grill
CMG
$41.3B
$123M 0.34%
3,313,041
-1,710,662
-34% -$61.9M
DBD icon
80
Diebold Nixdorf
DBD
$2.44B
$122M 0.34%
1,802,571
-17,157
-0.9% -$1.07M
FRPT icon
81
Freshpet
FRPT
$3.48B
$119M 0.33%
1,952,767
+461,444
+31% +$26.2M
POOL icon
82
Pool Corp
POOL
$7.25B
$119M 0.33%
519,836
-35,394
-6% -$9.21M
NXT icon
83
Nextpower Inc
NXT
$15.7B
$119M 0.33%
1,362,794
-106,844
-7% -$9.69M
EYE icon
84
National Vision
EYE
$1.54B
$116M 0.32%
4,510,895
-329,578
-7% -$8.86M
EXP icon
85
Eagle Materials
EXP
$6.47B
$115M 0.32%
558,744
-56,506
-9% -$12.5M
BFAM icon
86
Bright Horizons
BFAM
$3.76B
$114M 0.32%
1,129,039
-136,079
-11% -$13.7M
MANH icon
87
Manhattan Associates
MANH
$11.2B
$114M 0.32%
660,294
-87,634
-12% -$16M
OWL icon
88
Blue Owl Capital
OWL
$19.1B
$114M 0.32%
+7,615,956
New +$119M
GRAB icon
89
Grab
GRAB
$14.7B
$113M 0.32%
22,676,283
-1,588,265
-7% -$8.78M
EVR icon
90
Evercore
EVR
$11.5B
$113M 0.31%
331,027
-42,121
-11% -$13.5M
EXLS icon
91
EXL Service
EXLS
$5.2B
$110M 0.31%
2,584,072
-313,016
-11% -$12.8M
NOVT icon
92
Novanta
NOVT
$6.32B
$108M 0.3%
908,906
-51,667
-5% -$5.88M
PEN icon
93
Penumbra
PEN
$12.9B
$108M 0.3%
+345,974
New +$95.6M
INSP icon
94
Inspire Medical Systems
INSP
$1.68B
$107M 0.3%
1,161,285
-136,288
-11% -$13M
RRX icon
95
Regal Rexnord
RRX
$11.5B
$107M 0.3%
759,283
+356,279
+88% +$50.7M
GTX icon
96
Garrett Motion
GTX
$5.47B
$106M 0.29%
6,059,287
-1,656,537
-21% -$26.4M
WGS icon
97
GeneDx Holdings
WGS
$2.46B
$105M 0.29%
809,210
-410,928
-34% -$56.4M
CART icon
98
Maplebear
CART
$11.2B
$99.9M 0.28%
2,220,018
-957,810
-30% -$39.2M
BSY icon
99
Bentley Systems
BSY
$10.8B
$99.8M 0.28%
2,615,173
-316,123
-11% -$14.4M
WMS icon
100
Advanced Drainage Systems
WMS
$10.6B
$99.6M 0.28%
688,047
-132,156
-16% -$19.1M
2 3
4
5 6

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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.