Largest positions
| Issuer | Class | Value | Share |
|---|---|---|---|
| Apple Inc.COM | COM | $1,658,473,962 | 4.3% |
| Amazon Com Inc.COM | COM | $1,400,277,006 | 3.6% |
| Microsoft Corp.COM | COM | $1,284,149,026 | 3.3% |
| Nvidia CorporationCOM | COM | $1,075,368,561 | 2.8% |
| Alphabet Inc.CAP STK CL C | CAP STK CL C | $1,043,639,186 | 2.7% |
| Alphabet Inc.CAP STK CL A | CAP STK CL A | $858,624,702 | 2.2% |
| GE Vernova Inc.COM | COM | $775,022,876 | 2.0% |
| JPMORGAN Chase & COCOM | COM | $743,156,822 | 1.9% |
| State Str SPDR S&P 500 ETF TTR UNIT | TR UNIT | $633,286,009 | 1.6% |
| Visa Inc.COM CL A | COM CL A | $631,835,921 | 1.6% |
| Costco Wholesale CorporationCOM | COM | $490,833,719 | 1.3% |
| Idexx Labs Inc.COM | COM | $483,564,860 | 1.3% |
| Amphenol Corp.CL A | CL A | $441,577,319 | 1.2% |
| Mastercard IncorporatedCL A | CL A | $432,630,792 | 1.1% |
| Invesco Exchange Traded FD TS&P500 EQL WGT | S&P500 EQL WGT | $421,793,485 | 1.1% |
| Palo Alto Networks Inc.COM | COM | $418,267,566 | 1.1% |
| Eli Lilly & COCOM | COM | $416,319,968 | 1.1% |
| Meta Platforms Inc.CL A | CL A | $377,900,414 | 1.0% |
| Vanguard Intl Equity Index FALLWRLD EX US | ALLWRLD EX US | $375,134,515 | 1.0% |
| Micron Technology Inc.COM | COM | $364,615,192 | 0.9% |
| iShares TRCORE S&P500 ETF | CORE S&P500 ETF | $362,990,262 | 0.9% |
| Fastenal COCOM | COM | $355,761,040 | 0.9% |
| Broadcom Inc.COM | COM | $351,200,187 | 0.9% |
| Abbvie Inc.COM | COM | $324,076,456 | 0.8% |
| Vanguard Tax-managed FdsVAN FTSE DEV MKT | VAN FTSE DEV MKT | $305,735,367 | 0.8% |
| Bwx Technologies Inc.COM | COM | $302,956,557 | 0.8% |
| Vanguard Index FdsS&P 500 ETF SHS | S&P 500 ETF SHS | $288,028,908 | 0.8% |
| Arista Networks Inc.COM SHS | COM SHS | $272,609,153 | 0.7% |
| Vanguard Index FdsVALUE ETF | VALUE ETF | $268,598,032 | 0.7% |
| Invesco Qqq TRUNIT SER 1 | UNIT SER 1 | $264,528,652 | 0.7% |
| Walmart Inc.COM | COM | $257,199,781 | 0.7% |
| Home Depot Inc.COM | COM | $246,025,938 | 0.6% |
| Johnson & JohnsonCOM | COM | $242,861,932 | 0.6% |
| Berkshire Hathaway Inc. DelCL B NEW | CL B NEW | $241,981,741 | 0.6% |
| Everpure Inc.CL A | CL A | $240,159,308 | 0.6% |
| Ecolab Inc.COM | COM | $238,014,780 | 0.6% |
| Watsco Inc.COM | COM | $235,045,592 | 0.6% |
| American Express COCOM | COM | $230,118,643 | 0.6% |
| Progressive Corp.COM | COM | $225,900,097 | 0.6% |
| Servicenow Inc.COM | COM | $222,390,177 | 0.6% |
| Transdigm Group Inc.COM | COM | $219,733,476 | 0.6% |
| Stryker CorporationCOM | COM | $215,474,067 | 0.6% |
| iShares TRRUSSELL 2000 ETF | RUSSELL 2000 ETF | $210,630,787 | 0.5% |
| Crowdstrike Hldgs Inc.CL A | CL A | $207,753,341 | 0.5% |
| Uber Technologies Inc.COM | COM | $201,657,621 | 0.5% |
| Vanguard Index FdsTOTAL STK MKT | TOTAL STK MKT | $195,575,374 | 0.5% |
| Aaon Inc.COM PAR $0.004 | COM PAR $0.004 | $194,531,388 | 0.5% |
| Boeing COCOM | COM | $190,146,384 | 0.5% |
| Danaher Corp. DelCOM | COM | $184,974,108 | 0.5% |
| Cintas Corp.COM | COM | $180,885,157 | 0.5% |
Apple Inc.COM$1,658,473,962
- Class
- COM
- Share
- 4.3%
Amazon Com Inc.COM$1,400,277,006
- Class
- COM
- Share
- 3.6%
Microsoft Corp.COM$1,284,149,026
- Class
- COM
- Share
- 3.3%
Nvidia CorporationCOM$1,075,368,561
- Class
- COM
- Share
- 2.8%
Alphabet Inc.CAP STK CL C$1,043,639,186
- Class
- CAP STK CL C
- Share
- 2.7%
Alphabet Inc.CAP STK CL A$858,624,702
- Class
- CAP STK CL A
- Share
- 2.2%
GE Vernova Inc.COM$775,022,876
- Class
- COM
- Share
- 2.0%
JPMORGAN Chase & COCOM$743,156,822
- Class
- COM
- Share
- 1.9%
State Str SPDR S&P 500 ETF TTR UNIT$633,286,009
- Class
- TR UNIT
- Share
- 1.6%
Visa Inc.COM CL A$631,835,921
- Class
- COM CL A
- Share
- 1.6%
Costco Wholesale CorporationCOM$490,833,719
- Class
- COM
- Share
- 1.3%
Idexx Labs Inc.COM$483,564,860
- Class
- COM
- Share
- 1.3%
Amphenol Corp.CL A$441,577,319
- Class
- CL A
- Share
- 1.2%
Mastercard IncorporatedCL A$432,630,792
- Class
- CL A
- Share
- 1.1%
Invesco Exchange Traded FD TS&P500 EQL WGT$421,793,485
- Class
- S&P500 EQL WGT
- Share
- 1.1%
Palo Alto Networks Inc.COM$418,267,566
- Class
- COM
- Share
- 1.1%
Eli Lilly & COCOM$416,319,968
- Class
- COM
- Share
- 1.1%
Meta Platforms Inc.CL A$377,900,414
- Class
- CL A
- Share
- 1.0%
Vanguard Intl Equity Index FALLWRLD EX US$375,134,515
- Class
- ALLWRLD EX US
- Share
- 1.0%
Micron Technology Inc.COM$364,615,192
- Class
- COM
- Share
- 0.9%
iShares TRCORE S&P500 ETF$362,990,262
- Class
- CORE S&P500 ETF
- Share
- 0.9%
Fastenal COCOM$355,761,040
- Class
- COM
- Share
- 0.9%
Broadcom Inc.COM$351,200,187
- Class
- COM
- Share
- 0.9%
Abbvie Inc.COM$324,076,456
- Class
- COM
- Share
- 0.8%
Vanguard Tax-managed FdsVAN FTSE DEV MKT$305,735,367
- Class
- VAN FTSE DEV MKT
- Share
- 0.8%
Bwx Technologies Inc.COM$302,956,557
- Class
- COM
- Share
- 0.8%
Vanguard Index FdsS&P 500 ETF SHS$288,028,908
- Class
- S&P 500 ETF SHS
- Share
- 0.8%
Arista Networks Inc.COM SHS$272,609,153
- Class
- COM SHS
- Share
- 0.7%
Vanguard Index FdsVALUE ETF$268,598,032
- Class
- VALUE ETF
- Share
- 0.7%
Invesco Qqq TRUNIT SER 1$264,528,652
- Class
- UNIT SER 1
- Share
- 0.7%
Walmart Inc.COM$257,199,781
- Class
- COM
- Share
- 0.7%
Home Depot Inc.COM$246,025,938
- Class
- COM
- Share
- 0.6%
Johnson & JohnsonCOM$242,861,932
- Class
- COM
- Share
- 0.6%
Berkshire Hathaway Inc. DelCL B NEW$241,981,741
- Class
- CL B NEW
- Share
- 0.6%
Everpure Inc.CL A$240,159,308
- Class
- CL A
- Share
- 0.6%
Ecolab Inc.COM$238,014,780
- Class
- COM
- Share
- 0.6%
Watsco Inc.COM$235,045,592
- Class
- COM
- Share
- 0.6%
American Express COCOM$230,118,643
- Class
- COM
- Share
- 0.6%
Progressive Corp.COM$225,900,097
- Class
- COM
- Share
- 0.6%
Servicenow Inc.COM$222,390,177
- Class
- COM
- Share
- 0.6%
Transdigm Group Inc.COM$219,733,476
- Class
- COM
- Share
- 0.6%
Stryker CorporationCOM$215,474,067
- Class
- COM
- Share
- 0.6%
iShares TRRUSSELL 2000 ETF$210,630,787
- Class
- RUSSELL 2000 ETF
- Share
- 0.5%
Crowdstrike Hldgs Inc.CL A$207,753,341
- Class
- CL A
- Share
- 0.5%
Uber Technologies Inc.COM$201,657,621
- Class
- COM
- Share
- 0.5%
Vanguard Index FdsTOTAL STK MKT$195,575,374
- Class
- TOTAL STK MKT
- Share
- 0.5%
Aaon Inc.COM PAR $0.004$194,531,388
- Class
- COM PAR $0.004
- Share
- 0.5%
Boeing COCOM$190,146,384
- Class
- COM
- Share
- 0.5%
Danaher Corp. DelCOM$184,974,108
- Class
- COM
- Share
- 0.5%
Cintas Corp.COM$180,885,157
- Class
- COM
- Share
- 0.5%
The share class is shown on a wider screen.
The 50 largest of 1,998 positions by value, with holdings of the same security combined. The 200 largest are in this firm's machine-readable record. Share counts and quarter-on-quarter changes for each position are on EDGAR. View the full information table on EDGAR
This filing
- Form
- 13F-HR
- CIK
- 902367
- File number
- 028-04871
- Options
- 0 call, 0 put
- In the 25 largest
- 41.7%
- Prior quarter
- $34,895,892,190 at 31 March 2026
- Positions opened
- 167
- Positions closed
- 91
Common questions
What are William Blair & Company’s 13F holdings worth?
$38,388,159,607 across 1,998 positions for the quarter ended 30 June 2026.
What is William Blair & Company’s largest 13F holding?
APPLE INC (COM) was the largest position at $1,658,473,962, or 4.3% of reported 13F value, as of 30 June 2026.
How concentrated is William Blair & Company’s 13F portfolio?
The ten largest positions accounted for 26.3% of reported value and the twenty-five largest for 41.7%, across 1,998 positions as of 30 June 2026.
Does Form 13F show everything William Blair & Company manages?
No. Form 13F covers only long positions in exchange-traded securities over which the manager has investment discretion, valued at quarter end. It excludes cash, most bonds, private funds, and any assets the firm does not have discretion over, so it is neither the firm's total assets nor any individual client's portfolio.
How often does William Blair & Company file its 13F?
Every quarter. Managers file within 45 days of each quarter's end, so the figures are a snapshot that changes between filings. This page shows the quarter ended 30 June 2026.
Answered from this filing and the prior quarter's.