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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
(-0.82%)
Cap. Flow
-$212M
Cap. Flow
% of AUM
-0.57%
Top 10 Holdings %
Top 10 Hldgs %
27.41%
Holding
1,963
New
120
Increased
759
Reduced
753
Closed
96
Top Buys
| Rank | Stock | Value |
|---|---|---|
| 1 |
BWX Technologies
BWXT
|
+$46.6M |
| 2 |
Meta Platforms (Facebook)
META
|
+$38.3M |
| 3 |
ServiceNow
NOW
|
+$37.6M |
| 4 |
Vanguard FTSE All-World ex-US ETF
VEU
|
+$32.4M |
| 5 |
SPDR Gold Trust
GLD
|
+$29.4M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
FISV
Fiserv Inc
FISV
|
+$114M |
| 2 |
CoStar Group
CSGP
|
+$78.3M |
| 3 |
CWAN
Clearwater Analytics
CWAN
|
+$75.3M |
| 4 |
Pool Corp
POOL
|
+$54M |
| 5 |
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 | |
|---|---|---|---|---|---|---|
1951
Woodside Energy
WDS
$42.6B
| – | – |
-35,640
| Closed | -$536K |
|
1952
Warner Music
WMG
$13.8B
| – | – |
-6,017
| Closed | -$205K |
|
1953
Flutter Entertainment
FLUT
$16.4B
| – | – |
-918
| Closed | -$233K |
|
|
DAY
1954
DELISTED
Dayforce
DAY
| – | – |
-5,235
| Closed | -$361K |
|
|
GCTS
1955
GCT Semiconductor Holding
GCTS
$235M
| – | – |
-30,854
| Closed | -$46.9K |
|
|
SVCO
1956
Silvaco Group
SVCO
$256M
| – | – |
-24,000
| Closed | -$130K |
|
|
ALMS
1957
Alumis Inc
ALMS
$3.52B
| – | – |
-66,719
| Closed | -$266K |
|
|
PRMB
1958
Primo Brands
PRMB
$8.54B
| – | – |
-10,968
| Closed | -$242K |
|
|
RNTX
1959
Rein Therapeutics
RNTX
$69.9M
| – | – |
-23,393
| Closed | -$26.8K |
|
|
PTRN
1960
Pattern Group Inc
PTRN
$3.91B
| – | – |
-18,500
| Closed | -$253K |
|
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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.