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William Blair & Company

William Blair & Company Portfolio holdings

AUM $34.9B
1-Year Est. Return 18.88%
This Fund
S&P 500
This Quarter Est. Return
+12.61%
1 Year Est. Return
+18.88%
3 Year Est. Return
+73.84%
5 Year Est. Return
+90.13%
10 Year Est. Return
+512.03%
AUM
$36B
AUM Growth
+$2.85B
Cap. Flow
-$222M
Cap. Flow %
-0.62%
Top 10 Hldgs %
24.91%
Holding
1,911
New
111
Increased
662
Reduced
757
Closed
87

Top Buys

Rank Stock Value
1
GEV icon
GE Vernova
GEV
+$116M
2
BA icon
Boeing
BA
+$34M
3
CWAN
Clearwater Analytics
CWAN
+$31.2M
4
NVDA icon
NVIDIA
NVDA
+$27.5M
5
NET icon
Cloudflare
NET
+$26.2M

Top Sells

Rank Stock Value
1
XYZ
Block Inc
XYZ
+$79.4M
2
ZTS icon
Zoetis
ZTS
+$41.3M
3
ACN icon
Accenture
ACN
+$40.8M
4
IJH icon
iShares Core S&P Mid-Cap ETF
IJH
+$40.7M
5
UNH icon
UnitedHealth
UNH
+$36.4M

Sector Composition

Rank Sector Weight
1 Technology 27.47%
2 Financials 13.92%
3 Industrials 12.94%
4 Healthcare 11.51%
5 Consumer Discretionary 7.98%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow
MSFT icon
1
Microsoft
MSFT
$2.84T
$1.84B 5.11%
3,696,704
-69,498
-2% -$30.2M
AMZN icon
2
Amazon
AMZN
$2.5T
$1.34B 3.73%
6,121,875
-28,981
-0.5% -$5.74M
AAPL icon
3
Apple
AAPL
$4.89T
$1.24B 3.43%
6,026,880
-147,390
-2% -$29.8M
NVDA icon
4
NVIDIA
NVDA
$5.01T
$885M 2.46%
5,599,138
+218,564
+4% +$27.5M
V icon
5
Visa
V
$677B
$735M 2.04%
2,071,053
+34,297
+2% +$12M
JPM icon
6
JPMorgan Chase
JPM
$939B
$675M 1.88%
2,329,745
+10,609
+0.5% +$2.71M
IDXX icon
7
Idexx Laboratories
IDXX
$42.9B
$580M 1.61%
1,080,505
-10,265
-0.9% -$4.91M
MA icon
8
Mastercard
MA
$477B
$566M 1.57%
1,007,323
-13,372
-1% -$7.4M
GOOG icon
9
Alphabet (Google) Class C
GOOG
$3.9T
$564M 1.57%
3,180,029
-35,649
-1% -$5.89M
COST icon
10
Costco
COST
$415B
$546M 1.52%
551,986
+3,087
+0.6% +$3.07M
SPY icon
11
State Street SPDR S&P 500 ETF Trust
SPY
$778B
$531M 1.48%
859,665
+5,282
+0.6% +$3.02M
GOOGL icon
12
Alphabet (Google) Class A
GOOGL
$3.91T
$445M 1.24%
2,525,136
-59,067
-2% -$9.67M
META icon
13
Meta Platforms (Facebook)
META
$1.51T
$426M 1.18%
576,598
+25,440
+5% +$15.7M
UBER icon
14
Uber
UBER
$134B
$403M 1.12%
4,324,033
+75,224
+2% +$6.19M
PGR icon
15
Progressive
PGR
$124B
$402M 1.12%
1,505,421
-17,637
-1% -$4.83M
VEEV icon
16
Veeva Systems
VEEV
$30.3B
$370M 1.03%
1,284,962
-13,959
-1% -$3.46M
SYK icon
17
Stryker
SYK
$127B
$366M 1.02%
924,257
-2,118
-0.2% -$792K
FISV
18
Fiserv Inc
FISV
$27.2B
$363M 1.01%
2,107,519
+117,508
+6% +$21.3M
WSO icon
19
Watsco Inc
WSO
$14.9B
$356M 0.99%
806,656
-8,056
-1% -$3.74M
NOW icon
20
ServiceNow
NOW
$102B
$337M 0.94%
1,638,940
+8,385
+0.5% +$1.58M
GEV icon
21
GE Vernova
GEV
$270B
$335M 0.93%
632,806
+279,604
+79% +$116M
ICE icon
22
Intercontinental Exchange
ICE
$82.4B
$322M 0.89%
1,752,889
-21,406
-1% -$3.68M
APH icon
23
Amphenol
APH
$188B
$293M 0.82%
2,971,448
-55,902
-2% -$4.57M
FAST icon
24
Fastenal
FAST
$54B
$287M 0.8%
6,822,973
+237,705
+4% +$9.64M
HD icon
25
Home Depot
HD
$332B
$278M 0.77%
759,360
-2,549
-0.3% -$922K
1
2 3 4 5

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William Blair & Company's Q2 2025 Portfolio in Review

As of Q2 2025, William Blair & Company held 1,911 positions worth $36B, up 8.6% from $33.2B the previous quarter. Its ten largest holdings account for 25% of the portfolio.

William Blair & Company's Q2 2025 filing shows 111 new, 662 increased, 757 reduced and 87 closed positions. Its largest new stake was Affirm: 304,959 shares worth $21.1M. The largest sale was Block Inc, an estimated $79.4M.

By sector, the portfolio is most concentrated in Technology at 27% of assets, up from 26% a quarter earlier, followed by Financials and Industrials.

  • William Blair & Company's largest Q2 2025 buy was Affirm: 304,959 shares worth $21.1M.
  • William Blair & Company added most to GE Vernova in Q2 2025, an estimated $116M increase.
  • William Blair & Company's biggest Q2 2025 reduction was Block Inc, cutting an estimated $79.4M.
  • William Blair & Company fully exited Discover Financial Services in Q2 2025, selling an estimated $5.21M.
  • William Blair & Company's ten largest holdings make up 25% of its $36B portfolio in Q2 2025.
  • William Blair & Company opened 111 new positions and closed 87 in Q2 2025.
  • William Blair & Company's portfolio value rose 8.6% quarter-over-quarter to $36B.

Based on William Blair & Company's 13F filing for Q2 2025, filed 24 Jul 2025.