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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
PRFZ icon
1276
Invesco FTSE RAFI US 1500 Small-Mid ETF
PRFZ
$2.87B
$327K ﹤0.01%
7,122
+250
+4% +$11.4K
IWX icon
1277
iShares Russell Top 200 Value ETF
IWX
$4.05B
$325K ﹤0.01%
3,543
– –
FAF icon
1278
First American
FAF
$7.37B
$325K ﹤0.01%
5,294
+72
+1% +$4.51K
LOPE icon
1279
Grand Canyon Education
LOPE
$3.82B
$325K ﹤0.01%
1,952
+155
+9% +$28K
IFF icon
1280
International Flavors & Fragrances
IFF
$21.7B
$322K ﹤0.01%
4,781
-2,670
-36% -$173K
FUTY icon
1281
Fidelity MSCI Utilities Index ETF
FUTY
$2.27B
$322K ﹤0.01%
5,833
-400
-6% -$22.9K
EMN icon
1282
Eastman Chemical
EMN
$8.39B
$321K ﹤0.01%
5,024
+459
+10% +$28.3K
GRBK icon
1283
Green Brick Partners
GRBK
$3.03B
$320K ﹤0.01%
5,105
– –
DUOL icon
1284
Duolingo
DUOL
$6.42B
$318K ﹤0.01%
1,814
-5,867
-76% -$1.38M
BBAI icon
1285
BigBear.ai
BBAI
$1.55B
$318K ﹤0.01%
58,930
-5,026
-8% -$32.8K
IPAY icon
1286
Amplify Mobile Payments ETF
IPAY
$182M
$318K ﹤0.01%
6,115
– –
AMPX icon
1287
Amprius Technologies
AMPX
$1.73B
$317K ﹤0.01%
40,152
+15,364
+62% +$176K
IKT icon
1288
Inhibikase Therapeutics
IKT
$386M
$314K ﹤0.01%
152,953
– –
NIC icon
1289
Nicolet Bankshares
NIC
$3.63B
$312K ﹤0.01%
2,574
+770
+43% +$97.3K
ARW icon
1290
Arrow Electronics
ARW
$10.3B
$311K ﹤0.01%
2,826
+53
+2% +$6.02K
CVCO icon
1291
Cavco Industries
CVCO
$4.48B
$311K ﹤0.01%
526
-20
-4% -$11.3K
EUFN icon
1292
iShares MSCI Europe Financials ETF
EUFN
$4.29B
$310K ﹤0.01%
8,358
+52
+0.6% +$1.81K
MSCI icon
1293
MSCI
MSCI
$40.9B
$310K ﹤0.01%
540
-89
-14% -$49.9K
USIG icon
1294
iShares Broad USD Investment Grade Corporate Bond ETF
USIG
$17.3B
$310K ﹤0.01%
5,982
+1,923
+47% +$100K
LUMN icon
1295
Lumen
LUMN
$6.85B
$309K ﹤0.01%
39,814
+2,806
+8% +$23.1K
CMS icon
1296
CMS Energy
CMS
$21.7B
$309K ﹤0.01%
4,415
-1,183
-21% -$86K
VIA
1297
Via Transportation Inc
VIA
$1.9B
$308K ﹤0.01%
10,616
-5,284
-33% -$218K
TM icon
1298
Toyota
TM
$224B
$307K ﹤0.01%
1,433
+3
+0.2% +$609
CCEP icon
1299
Coca-Cola Europacific Partners
CCEP
$46.9B
$306K ﹤0.01%
3,374
-8
-0.2% -$723
MCY icon
1300
Mercury Insurance
MCY
$5.92B
$306K ﹤0.01%
3,251
– –
50 51
52
53 54

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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.