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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
-3.16%
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
$34.9B
AUM Growth
-$2.36B
Cap. Flow
-$465K
Cap. Flow %
-0%
Top 10 Hldgs %
25.64%
Holding
2,019
New
132
Increased
799
Reduced
746
Closed
97

Top Buys

Rank Stock Value
1
RSP icon
Invesco S&P 500 Equal Weight ETF
RSP
+$224M
2
VEU icon
Vanguard FTSE All-World ex-US ETF
VEU
+$113M
3
PWR icon
Quanta Services
PWR
+$75M
4
GLD icon
SPDR Gold Trust
GLD
+$58.9M
5
BA icon
Boeing
BA
+$55.5M

Top Sells

Rank Stock Value
1
WDAY icon
Workday
WDAY
+$91.2M
2
CWAN
Clearwater Analytics
CWAN
+$78M
3
APP icon
Applovin
APP
+$74.7M
4
TYL icon
Tyler Technologies
TYL
+$69.1M
5
UBER icon
Uber
UBER
+$62.2M

Sector Composition

Rank Sector Weight
1 Technology 21.79%
2 Industrials 14.2%
3 Financials 12.26%
4 Healthcare 10.59%
5 Consumer Discretionary 7.17%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow
AXSM icon
651
Axsome Therapeutics
AXSM
$11.7B
$2.76M 0.01%
16,308
-30,532
-65% -$5.27M
MGV icon
652
Vanguard Mega Cap Value ETF
MGV
$13.1B
$2.75M 0.01%
18,984
-16,966
-47% -$2.51M
VST icon
653
Vistra
VST
$48.2B
$2.75M 0.01%
18,261
-7,036
-28% -$1.14M
ELS icon
654
Equity Lifestyle Properties
ELS
$13.1B
$2.74M 0.01%
43,973
+172
+0.4% +$11.1K
TWST icon
655
Twist Bioscience
TWST
$5.32B
$2.73M 0.01%
57,417
-24,144
-30% -$1.08M
ZAP
656
Global X U.S. Electrification ETF
ZAP
$453M
$2.71M 0.01%
84,160
+17,307
+26% +$546K
RYN icon
657
Rayonier
RYN
$6.67B
$2.7M 0.01%
+130,939
New +$2.89M
KKR icon
658
KKR & Co
KKR
$89.1B
$2.69M 0.01%
29,042
+259
+0.9% +$27.3K
BDEC icon
659
Innovator US Equity Buffer ETF December
BDEC
$214M
$2.68M 0.01%
55,931
-4,860
-8% -$240K
WTFC icon
660
Wintrust Financial
WTFC
$10.7B
$2.62M 0.01%
18,856
+104
+0.6% +$15.1K
NEM icon
661
Newmont
NEM
$96.2B
$2.61M 0.01%
24,126
+2,243
+10% +$259K
IWS icon
662
iShares Russell Mid-Cap Value ETF
IWS
$15.7B
$2.61M 0.01%
17,908
+50
+0.3% +$7.42K
IYR icon
663
iShares US Real Estate ETF
IYR
$4.75B
$2.58M 0.01%
27,278
+6,839
+33% +$664K
AFRM icon
664
Affirm
AFRM
$23.5B
$2.57M 0.01%
56,198
-264,485
-82% -$15.3M
OKLO
665
Oklo
OKLO
$6.41B
$2.55M 0.01%
51,430
-10,466
-17% -$752K
IONS icon
666
Ionis Pharmaceuticals
IONS
$8.93B
$2.54M 0.01%
33,857
+69
+0.2% +$5.45K
CBRE icon
667
CBRE Group
CBRE
$43.3B
$2.53M 0.01%
18,671
+1,542
+9% +$234K
IBB icon
668
iShares Biotechnology ETF
IBB
$9.45B
$2.5M 0.01%
14,777
+3,101
+27% +$530K
SHV icon
669
iShares 0-1 Year Treasury Bond ETF
SHV
$20.8B
$2.48M 0.01%
22,441
-273
-1% -$30.1K
DSI icon
670
iShares MSCI KLD 400 Social ETF
DSI
$5.1B
$2.47M 0.01%
20,396
-1,952
-9% -$250K
LITE icon
671
Lumentum
LITE
$46.9B
$2.46M 0.01%
3,508
-103
-3% -$56.6K
QNST icon
672
QuinStreet
QNST
$927M
$2.46M 0.01%
205,144
+6,751
+3% +$85.6K
GGG icon
673
Graco
GGG
$13.2B
$2.46M 0.01%
29,070
+13,838
+91% +$1.23M
PCAR icon
674
PACCAR
PCAR
$70.5B
$2.46M 0.01%
21,265
-1,351
-6% -$163K
WSC icon
675
WillScot Mobile Mini Holdings
WSC
$4.37B
$2.44M 0.01%
140,839
-37,594
-21% -$768K
25 26
27
28 29

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William Blair & Company's Q1 2026 Portfolio in Review

As of Q1 2026, William Blair & Company held 2,019 positions worth $34.9B, down 6.3% from $37.3B the previous quarter. Its ten largest holdings account for 26% of the portfolio.

William Blair & Company's Q1 2026 filing shows 132 new, 799 increased, 746 reduced and 97 closed positions. Its largest new stake was Silicon Motion: 103,179 shares worth $11.6M. The largest sale was Workday, an estimated $91.2M.

By sector, the portfolio is most concentrated in Technology at 22% of assets, down from 26% a quarter earlier, followed by Industrials and Financials.

  • William Blair & Company's largest Q1 2026 buy was Silicon Motion: 103,179 shares worth $11.6M.
  • William Blair & Company added most to Invesco S&P 500 Equal Weight ETF in Q1 2026, an estimated $224M increase.
  • William Blair & Company's biggest Q1 2026 reduction was Workday, cutting an estimated $91.2M.
  • William Blair & Company fully exited Dynavax Technologies in Q1 2026, selling an estimated $27.4M.
  • William Blair & Company's ten largest holdings make up 26% of its $34.9B portfolio in Q1 2026.
  • William Blair & Company opened 132 new positions and closed 97 in Q1 2026.
  • William Blair & Company's portfolio value fell 6.3% quarter-over-quarter to $34.9B.

Based on William Blair & Company's 13F filing for Q1 2026, filed 8 May 2026.