1y return+19.3%S&P 500 +20.9%
3y return+51.0%S&P 500 +68.5%
5y return+33.6%S&P 500 +74.5%
10y return+227.4%S&P 500 +256.5%
These returns are for its stock picks as disclosed on Form 13F: last quarter's holdings, valued at this quarter's prices. They miss trades within each quarter, short positions, options, bonds, cash and fees, so they aren't the returns its clients got.
$100 invested in its stock picks
Since June 30, 2016: $327 against $357 in the S&P 500.2
William Blair Investment Management, LLCS&P 500 (SPY)
Top holdings
At the end of June 30, 2026. Change is in shares since the quarter before.2
| Stock | Value | Share of portfolio | Change |
|---|---|---|---|
| TSMTaiwan Semiconductor Manufac | $2.4B | 7.1% | −10.5% |
| NVDANvidia Corporation | $1.7B | 5.2% | −3.8% |
| GOOGLAlphabet Inc | $1.1B | 3.4% | +27.4% |
| AAPLApple Inc | $943.3M | 2.8% | −32.3% |
| AVGOBroadcom Inc | $776.7M | 2.3% | −6.6% |
| MSFTMicrosoft Corp | $764.2M | 2.3% | −29.3% |
| METAMeta Platforms Inc | $535.2M | 1.6% | −6.2% |
| AMZNAmazon Com Inc | $473.6M | 1.4% | −37.2% |
| MAMastercard Incorporated | $471.5M | 1.4% | −13.4% |
| AMDAdvanced Micro Devices Inc | $443.5M | 1.3% | −26.8% |
| AMATApplied Matls Inc | $360.0M | 1.1% | +1325.1% |
| GEGe Aerospace | $295.5M | 0.9% | New |
| Astrazeneca PLCCUSIP G0593M107 | $283.2M | 0.9% | −22.0% |
| PRMBPrimo Brands Corporation | $279.3M | 0.8% | −12.5% |
| PEverpure Inc | $272.2M | 0.8% | +19.9% |
| APHAmphenol Corp | $270.7M | 0.8% | +42.5% |
| Linde PLCCUSIP G54950103 | $262.0M | 0.8% | −20.6% |
| ONTOOnto Innovation Inc | $251.8M | 0.8% | −31.0% |
| BWABorgwarner Inc | $251.3M | 0.8% | +31.2% |
| CGCarlyle Group Inc | $249.1M | 0.7% | −6.1% |
| ARGXArgenx Se | $245.5M | 0.7% | |
| MLIMueller Inds Inc | $244.2M | 0.7% | −5.9% |
| MNSTMonster Beverage Corp New | $244.0M | 0.7% | −13.5% |
| FFIVF5 Inc | $243.9M | 0.7% | −9.8% |
| Credicorp LtdCUSIP G2519Y108 | $243.5M | 0.7% |
Best picks still held
How each current holding has done since the quarter it first appeared in its filings (up to six years back).
| Stock | Held since | Return since | Now worth |
|---|---|---|---|
| AMDAdvanced Micro Devices Inc | June 30, 2020 | +1004.1% | $443.5M |
| NVDANvidia Corporation | June 30, 2021 | +900.3% | $1.7B |
| TSMTaiwan Semiconductor Manufac | June 30, 2020 | +741.2% | $2.4B |
| GOOGLAlphabet Inc | June 30, 2020 | +404.0% | $1.1B |
| PEverpure Inc | June 30, 2020 | +354.6% | $272.2M |
| AMATApplied Matls Inc | December 31, 2023 | +346.1% | $360.0M |
| ONTOOnto Innovation Inc | March 31, 2025 | +211.9% | $251.8M |
| Credicorp LtdCUSIP G2519Y108 | June 30, 2020 | +191.4% | $243.5M |
| KRYSKrystal Biotech Inc | June 30, 2025 | +170.4% | $211.9M |
| METAMeta Platforms Inc | June 30, 2020 | +148.1% | $535.2M |
Sold off last quarter
- COHRCoherent Corp was $159.2M
- VEEVVeeva Sys Inc was $113.0M
- DOCSDoximity Inc was $112.6M
- PLNTPlanet Fitness Master Issuer was $108.0M
- POOLPool Corp was $91.5M
- WMSAdvanced Drain Sys Inc Del was $89.9M
- PSNParsons Corp Del was $80.6M
- TYLTyler Technologies Inc was $73.9M
- INSPInspire Med Sys Inc was $58.7M
- Spotify Technology S ACUSIP L8681T102 was $51.9M
Quarter by quarter
| Quarter | Its picks | S&P 500 |
|---|---|---|
| June 30, 2026 | +18.1% | +14.8% |
| March 31, 2026 | −5.6% | −4.6% |
| December 31, 2025 | +0.7% | +2.4% |
| September 30, 2025 | +6.3% | +7.8% |
| June 30, 2025 | +12.3% | +10.5% |
| March 31, 2025 | −8.8% | −4.6% |
| December 31, 2024 | +1.0% | +2.1% |
| September 30, 2024 | +5.4% | +5.4% |
| June 30, 2024 | −1.0% | +4.0% |
| March 31, 2024 | +8.8% | +10.0% |
| December 31, 2023 | +13.3% | +11.2% |
| September 30, 2023 | −4.8% | −3.6% |
| June 30, 2023 | +6.9% | +8.3% |
| March 31, 2023 | +7.2% | +7.0% |
| December 31, 2022 | +7.4% | +7.1% |
| September 30, 2022 | −3.2% | −5.3% |
| June 30, 2022 | −20.5% | −16.5% |
| March 31, 2022 | −10.1% | −4.9% |
| December 31, 2021 | +3.3% | +10.7% |
| September 30, 2021 | +0.5% | +0.3% |
Sources
Every number on this page points here. Each one links to the public record.
- 1SEC EDGAR: William Blair Investment Management, LLC Form 13F filingshttps://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=1644956&type=13F-HR&dateb=&owner=include&count=40CIK 1644956
- 2SEC: 13F for the quarter ended June 30, 2026https://www.sec.gov/Archives/edgar/data/1644956/000164495626000023/Filed August 12, 2026 · accession 0001644956-26-000023