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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
+1.73%
1 Year Est. Return
+18.88%
3 Year Est. Return
+73.84%
5 Year Est. Return
+90.13%
10 Year Est. Return
+563.35%
AUM
$37.3B
AUM Growth
-$310M
Cap. Flow
-$212M
Cap. Flow %
-0.57%
Top 10 Hldgs %
27.41%
Holding
1,963
New
120
Increased
759
Reduced
753
Closed
96

Top Buys

Rank Stock Value
1
BWXT icon
BWX Technologies
BWXT
+$46.6M
2
META icon
Meta Platforms (Facebook)
META
+$38.3M
3
NOW icon
ServiceNow
NOW
+$37.6M
4
VEU icon
Vanguard FTSE All-World ex-US ETF
VEU
+$32.4M
5
GLD icon
SPDR Gold Trust
GLD
+$29.4M

Top Sells

Rank Stock Value
1
FISV
Fiserv Inc
FISV
+$114M
2
CSGP icon
CoStar Group
CSGP
+$78.3M
3
CWAN
Clearwater Analytics
CWAN
+$75.3M
4
POOL icon
Pool Corp
POOL
+$54M
5
ZTS icon
Zoetis
ZTS
+$51.3M

Sector Composition

Rank Sector Weight
1 Technology 25.8%
2 Financials 13.4%
3 Industrials 12.04%
4 Healthcare 11.22%
5 Communication Services 7.63%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow
ITW icon
101
Illinois Tool Works
ITW
$84.5B
$91M 0.24%
369,427
-42,768
-10% -$10.7M
TMO icon
102
Thermo Fisher Scientific
TMO
$220B
$91M 0.24%
157,010
+22,886
+17% +$12.9M
PCOR icon
103
Procore
PCOR
$8.67B
$89.3M 0.24%
1,227,509
+1,980
+0.2% +$146K
EFA icon
104
iShares MSCI EAFE ETF
EFA
$80.2B
$89M 0.24%
926,883
+72,180
+8% +$6.85M
MRK icon
105
Merck
MRK
$318B
$87.8M 0.24%
834,024
+21,658
+3% +$2.03M
CW icon
106
Curtiss-Wright
CW
$25.5B
$86.5M 0.23%
157,001
+26,309
+20% +$14.7M
VRSK icon
107
Verisk Analytics
VRSK
$25B
$86.4M 0.23%
386,320
-10,371
-3% -$2.34M
MU icon
108
Micron Technology
MU
$991B
$85.6M 0.23%
299,970
+78
+0% +$17.9K
CWAN
109
DELISTED
Clearwater Analytics
CWAN
$81.4M 0.22%
3,372,960
-3,761,687
-53% -$75.3M
ITOT icon
110
iShares Core S&P Total US Stock Market ETF
ITOT
$97.8B
$80.4M 0.22%
540,800
+28,547
+6% +$4.21M
IEFA icon
111
iShares Core MSCI EAFE ETF
IEFA
$196B
$78.1M 0.21%
873,248
+102,379
+13% +$9.05M
RBA icon
112
RB Global
RBA
$17.5B
$77.3M 0.21%
751,879
-9,452
-1% -$960K
PEP icon
113
PepsiCo
PEP
$190B
$76.9M 0.21%
536,086
+32,447
+6% +$4.77M
IWV icon
114
iShares Russell 3000 ETF
IWV
$20.4B
$76.9M 0.21%
198,671
+3,019
+2% +$1.16M
HEI icon
115
HEICO Corp
HEI
$51.4B
$74.6M 0.2%
230,401
-1,602
-0.7% -$506K
NDAQ icon
116
Nasdaq
NDAQ
$52.9B
$73.8M 0.2%
759,873
+143,251
+23% +$12.9M
LOW icon
117
Lowe's Companies
LOW
$125B
$73.7M 0.2%
305,519
-12,266
-4% -$2.95M
SCHW
118
Charles Schwab
SCHW
$187B
$71.7M 0.19%
717,463
+2,058
+0.3% +$195K
SBUX icon
119
Starbucks
SBUX
$120B
$71.3M 0.19%
846,822
-67,028
-7% -$5.65M
BLK icon
120
Blackrock
BLK
$176B
$71.3M 0.19%
66,600
-3,410
-5% -$3.73M
IUSG icon
121
iShares Core S&P US Growth ETF
IUSG
$33.9B
$70.5M 0.19%
419,694
+118,987
+40% +$19.8M
RTX icon
122
RTX Corp
RTX
$301B
$69.1M 0.19%
376,802
+9,483
+3% +$1.65M
CAT icon
123
Caterpillar
CAT
$387B
$66.6M 0.18%
116,252
+636
+0.6% +$353K
ULS icon
124
UL Solutions
ULS
$15.8B
$66.4M 0.18%
841,568
-40,733
-5% -$3.27M
ALL icon
125
Allstate
ALL
$67.5B
$65.2M 0.17%
313,041
-42,534
-12% -$8.71M
3 4
5
6 7

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William Blair & Company's Q4 2025 Portfolio in Review

As of Q4 2025, William Blair & Company held 1,963 positions worth $37.3B, down 0.82% from $37.6B the previous quarter. Its ten largest holdings account for 27% of the portfolio.

William Blair & Company's Q4 2025 filing shows 120 new, 759 increased, 753 reduced and 96 closed positions. Its largest new stake was Wingstop: 90,773 shares worth $21.6M. The largest sale was Fiserv Inc, an estimated $114M.

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

  • William Blair & Company's largest Q4 2025 buy was Wingstop: 90,773 shares worth $21.6M.
  • William Blair & Company added most to BWX Technologies in Q4 2025, an estimated $46.6M increase.
  • William Blair & Company's biggest Q4 2025 reduction was Fiserv Inc, cutting an estimated $114M.
  • William Blair & Company fully exited SAP in Q4 2025, selling an estimated $9.19M.
  • William Blair & Company's ten largest holdings make up 27% of its $37.3B portfolio in Q4 2025.
  • William Blair & Company opened 120 new positions and closed 96 in Q4 2025.
  • William Blair & Company's portfolio value fell 0.82% quarter-over-quarter to $37.3B.

Based on William Blair & Company's 13F filing for Q4 2025, filed 17 Feb 2026.