BLAIR WILLIAM & CO/IL

New 13F: Q3 2026

BLAIR WILLIAM & CO/IL filed its 13F for the quarter ended Sep 30, 2026 on Nov 10, 2026: $14.4B in AI and semiconductor stocks; $151.9M bought and $449.3M sold against its previous quarter, at the quarter's prices.

BLAIR WILLIAM & CO/IL declares $14.0B in 152 of the 230 AI and semiconductor companies tracked on Silicon Floor, as of Jun 30, 2026 (Form 13F): 36.5% of its $38.4B 13F portfolio. Largest positions: Alphabet (0.04% of the company) and Apple (0.04% of the company). It is a private wealth platform: it holds shares for many client accounts, so its trades are left out of the quarter's moves on /holders. Over time: $14.0B in 152 of these companies for Q2 2026, against $3.9B in 90 for Q4 2019 (13F values as filed). From Mar 31, 2026 to Jun 30, 2026, it bought $350.6M and sold $492.9M of these stocks, at the quarter's prices: a net sale of $142.4M; 6 new positions and 1 sold out.

Performance of its AI picks

The AI-stock portfolio BLAIR WILLIAM & CO/IL declared for Q2 2026 (Form 13F), held unchanged, returned +4.5% in Q3 2026 (SMH -7.1%). Over the last 12 months, quarter after quarter: +23.3% (SMH +87.2%). Over three years, quarter after quarter: +112.0% (SMH +325.8%). Over five years, quarter after quarter: +109.4% (SMH +389.8%). Trades made during a quarter are not visible in 13F filings: this measures its declared picks, not the return of its funds.

Largest positions

  1. Alphabet (GOOGL): $1.9B, 5.4M shares, 0.04% of the company, 5.0% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  2. Apple (AAPL): $1.7B, 5.7M shares, 0.04% of the company, 4.3% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  3. Amazon (AMZN): $1.4B, 5.9M shares, 0.05% of the company, 3.6% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  4. Microsoft (MSFT): $1.3B, 3.4M shares, 0.05% of the company, 3.3% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  5. NVIDIA (NVDA): $1.1B, 5.4M shares, 0.02% of the company, 2.8% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  6. GE Vernova (GEV): $775.0M, 659,673 shares, 0.25% of the company, 2.0% of its portfolio (trimmed this quarter); held since Q2 2024
  7. Amphenol (APH): $441.6M, 5.0M shares, 0.20% of the company, 1.2% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  8. Palo Alto Networks (PANW): $418.3M, 1.2M shares, 0.15% of the company, 1.1% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  9. Meta Platforms (META): $377.9M, 670,881 shares, 0.03% of the company, 0.98% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  10. Micron (MU): $364.6M, 315,878 shares, 0.03% of the company, 0.95% of its portfolio (trimmed this quarter); held since Q4 2019 or earlier
  11. Broadcom (AVGO): $351.2M, 929,716 shares, 0.02% of the company, 0.91% of its portfolio (added this quarter); held since Q4 2019 or earlier
  12. BWX Technologies (BWXT): $303.0M, 1.6M shares, 1.7% of the company, 0.79% of its portfolio (added this quarter); held since Q4 2019 or earlier
  13. Arista Networks (ANET): $272.6M, 1.6M shares, 0.13% of the company, 0.71% of its portfolio (added this quarter); held since Q4 2019 or earlier
  14. ServiceNow (NOW): $222.4M, 2.2M shares, 0.22% of the company, 0.58% of its portfolio (added this quarter); held since Q4 2019 or earlier
  15. CrowdStrike (CRWD): $207.8M, 1.1M shares, 0.11% of the company, 0.54% of its portfolio (added this quarter); held since Q1 2020

By sector

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