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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
+10.81%
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
$38.7B
AUM Growth
+$994M
Cap. Flow
-$1.59B
Cap. Flow %
-4.12%
Top 10 Hldgs %
31.01%
Holding
462
New
45
Increased
110
Reduced
257
Closed
48

Top Buys

Rank Stock Value
1
GOOGL icon
Alphabet (Google) Class A
GOOGL
+$445M
2
NU icon
Nu Holdings
NU
+$175M
3
BSY icon
Bentley Systems
BSY
+$161M
4
CAVA icon
CAVA Group
CAVA
+$143M
5
SNOW icon
Snowflake
SNOW
+$111M

Top Sells

Rank Stock Value
1
DDOG icon
Datadog
DDOG
+$298M
2
AMZN icon
Amazon
AMZN
+$222M
3
META icon
Meta Platforms (Facebook)
META
+$181M
4
TLN
Talen Energy Corp
TLN
+$152M
5
EPAM icon
EPAM Systems
EPAM
+$149M

Sector Composition

Rank Sector Weight
1 Technology 38.52%
2 Consumer Discretionary 12.99%
3 Financials 12.96%
4 Healthcare 10.56%
5 Industrials 9.02%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow
CMG icon
51
Chipotle Mexican Grill
CMG
$41.3B
$197M 0.51%
5,023,703
-1,252,721
-20% -$56.4M
MRCY icon
52
Mercury Systems
MRCY
$6.7B
$193M 0.5%
2,487,957
-2,207,726
-47% -$137M
RACE icon
53
Ferrari
RACE
$71.6B
$191M 0.49%
394,449
-36,379
-8% -$17.4M
MDGL icon
54
Madrigal Pharmaceuticals
MDGL
$12.4B
$189M 0.49%
411,802
+61,513
+18% +$22.9M
BAM icon
55
Brookfield Asset Management
BAM
$87.1B
$181M 0.47%
3,177,123
-168,416
-5% -$10M
MLM icon
56
Martin Marietta Materials
MLM
$32.7B
$175M 0.45%
277,356
-9,359
-3% -$5.58M
CHE icon
57
Chemed
CHE
$7.07B
$172M 0.45%
385,124
+46,038
+14% +$20.8M
POOL icon
58
Pool Corp
POOL
$7.25B
$172M 0.45%
555,230
-31,080
-5% -$9.74M
CWST icon
59
Casella Waste Systems
CWST
$5.76B
$172M 0.44%
1,809,867
+9,712
+0.5% +$978K
CFLT
60
DELISTED
Confluent
CFLT
$170M 0.44%
8,569,807
-1,069,295
-11% -$22.4M
AMD icon
61
Advanced Micro Devices
AMD
$788B
$169M 0.44%
1,047,200
+440,296
+73% +$71.1M
CW icon
62
Curtiss-Wright
CW
$26.7B
$168M 0.44%
310,092
-52,130
-14% -$25.7M
PLNT icon
63
Planet Fitness
PLNT
$3.65B
$165M 0.43%
1,593,907
-145,037
-8% -$15.4M
DT icon
64
Dynatrace
DT
$14.3B
$165M 0.43%
3,397,838
-765,523
-18% -$38.7M
GMED icon
65
Globus Medical
GMED
$11.5B
$161M 0.42%
2,819,165
+414,134
+17% +$23.8M
QTWO icon
66
Q2 Holdings
QTWO
$3.9B
$155M 0.4%
2,141,005
+175,146
+9% +$14.4M
CWAN
67
DELISTED
Clearwater Analytics
CWAN
$155M 0.4%
8,576,372
-236,504
-3% -$4.79M
MANH icon
68
Manhattan Associates
MANH
$11.2B
$153M 0.4%
747,928
-160,406
-18% -$33.9M
APPF icon
69
AppFolio
APPF
$6.97B
$152M 0.39%
551,969
-181,459
-25% -$49M
BSY icon
70
Bentley Systems
BSY
$10.8B
$151M 0.39%
+2,931,296
New +$161M
FTAI icon
71
FTAI Aviation
FTAI
$23.3B
$151M 0.39%
902,875
-394,090
-30% -$56M
COHR icon
72
Coherent
COHR
$69.6B
$147M 0.38%
1,365,017
+945,853
+226% +$94.3M
PSN icon
73
Parsons
PSN
$5.16B
$146M 0.38%
1,764,619
-124,662
-7% -$9.64M
GRAB icon
74
Grab
GRAB
$14.7B
$146M 0.38%
24,264,548
+3,114,180
+15% +$16.5M
BWIN
75
Baldwin Insurance Group
BWIN
$3B
$144M 0.37%
5,104,695
-298,055
-6% -$10.3M
1 2
3
4 5

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William Blair Investment Management's Q3 2025 Portfolio in Review

As of Q3 2025, William Blair Investment Management held 462 positions worth $38.7B, up 2.6% from $37.7B the previous quarter. Its ten largest holdings account for 31% of the portfolio.

William Blair Investment Management withdrew a net $1.59B in Q3 2025, closing 48 positions and reducing 257 holdings. Its most notable exit was EPAM Systems, an estimated $149M position sold in full.

By sector, the portfolio is most concentrated in Technology at 39% of assets, up from 36% a quarter earlier, followed by Consumer Discretionary and Financials.

Against the trend, William Blair Investment Management opened a new position in Bentley Systems worth $151M.

  • William Blair Investment Management's largest Q3 2025 buy was Bentley Systems: 2,931,296 shares worth $151M.
  • William Blair Investment Management added most to Alphabet (Google) Class A in Q3 2025, an estimated $445M increase.
  • William Blair Investment Management's biggest Q3 2025 reduction was Datadog, cutting an estimated $298M.
  • William Blair Investment Management fully exited EPAM Systems in Q3 2025, selling an estimated $149M.
  • William Blair Investment Management's ten largest holdings make up 31% of its $38.7B portfolio in Q3 2025.
  • William Blair Investment Management opened 45 new positions and closed 48 in Q3 2025.
  • William Blair Investment Management's portfolio value rose 2.6% quarter-over-quarter to $38.7B.

Based on William Blair Investment Management's 13F filing for Q3 2025, filed 12 Nov 2025.