WB
William Blair Investment Management, LLC SEC 13F Holdings (Q2 2026) — Top Position: TAIWAN SEMICONDUCTOR-SP ADR
William Blair Investment Management, LLCCIK: 0001644956
Diversified strategyQuality / disciplined sizingSector-focused
Total reported value
$33.3B
Reporting period: 2026-06-30 · Number of holdings: 403
WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC disclosed 403 holdings in its latest 13F filing for the period ending 2026-06-30, with total reported value of $33.3B and a quarterly turnover rate of 42.5%.
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Personality snowflake
- Concentration
- 5.88
- Portfolio Stability
- 42.5
- Momentum
- 62.6
- Sector conviction
- 66.83
- Diversification
- 100
- Sizing Uniformity
- 77.77
William Blair Investment Management, LLC's disclosed holdings carry a Herfindahl concentration index of 0.015 — mathematically equivalent to about 68 equally-sized positions, well below its 403 actual disclosed holdings. That gap points to a strategy built around a small core of high-conviction bets rather than broad diversification.
Position sizes vary widely across the portfolio (a coefficient of variation of 2.22), with a handful of outsized bets alongside many smaller positions.
No strong tilt toward either adding to existing winners or initiating outsized new positions was observed in the latest reported quarter.
Source and citation information
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Recent moves
View source Form 13F filing on SEC.govTrim MSFT
-29.3% -$308.1M
Trim AAPL
-32.3% -$278.1M
Add GOOGL
+27.4% $420.1M
Add AMAT
+1325.1% $348.1M
Add TSM
-10.5% $491.9M
New buy GE
Holdings Map
New buyAddUnchangedTrim
Institutional Game-State Analysis
Core Intent
William Blair actively rotated within technology this quarter: adds in GOOGL and AMAT, new positions in GE and CRWD, while trimming TSM, MSFT, and AAPL. IT remains dominant at 41.2% of the portfolio, indicating a sector-internal repositioning rather than a broad de-risking.
Macro & Fundamentals
The flows suggest a possible shift from mega-cap software/consumer tech (MSFT, AAPL) toward semiconductor equipment (AMAT) and ad-supported platforms (GOOGL), with fresh exposure to industrials (GE) and cybersecurity (CRWD). This aligns with ongoing AI infrastructure spending trends, though the data is thin and should be treated as suggestive, not conclusive.
Blind Spots / Risks
The portfolio's heavy IT tilt leaves it vulnerable to sector-wide valuation compression or a liquidity squeeze in growth equities; even with 400+ holdings, the effective diversification may be overstated. The small new positions in GE and CRWD may be exploratory rather than committed, so their impact on future returns is uncertain.
Compiled by AI directly from this institution's public Form 13F data on SEC EDGAR; reflects historical positioning only and carries no investment recommendation. Source filing linked below. View the original 2026-06-30 Form 13F filing on SEC.gov
Top 10 holdings by weight
Full holdings list this quarter
Showing top 200 holdings (of 403 total)
| # | Ticker | Issuer | Asset Subclass | Weight | Weight Change | Shares Change | 4Q Trend |
|---|---|---|---|---|---|---|---|
| 1 | TSM | Taiwan Semiconductor-sp Adr | Stock-Tech | 7.09% | +0.93% | -10.54% | |
| 2 | NVDA | Nvidia CORP | Stock-Tech | 5.17% | +0.02% | -3.83% | |
| 3 | GOOGL | Alphabet Inc-cl A | Stock-Comm Services | 3.43% | +1.05% | +27.41% | |
| 4 | AAPL | Apple Inc | Stock-Tech | 2.84% | -1.20% | -32.26% | |
| 5 | AVGO | Broadcom Inc | Stock-Tech | 2.34% | +0.09% | -6.61% | |
| 6 | MSFT | Microsoft CORP | Stock-Tech | 2.30% | -1.24% | -29.28% | |
| 7 | META | Meta Platforms Inc-class A | Stock-Comm Services | 1.61% | -0.31% | -6.22% | |
| 8 | AMZN | Amazon.com Inc | Stock-Consumer Disc | 1.42% | -0.76% | -37.19% | |
| 9 | MA | Mastercard Inc - A | Stock-Financials | 1.42% | -0.33% | -13.45% | |
| 10 | AMD | Advanced Micro Devices | Stock-Tech | 1.33% | +0.63% | -26.77% | |
| 11 | AMAT | Applied Materials Inc | Stock-Tech | 1.08% | +1.04% | +1325.15% | |
| 12 | GE | General Electric | Stock-Industrials | 0.89% | +0.89% | NEW | |
| 13 | AZN | AstraZeneca PLC | Stock-Healthcare | 0.85% | -0.40% | -22.00% | |
| 14 | PRMB | Primo Brands CORP | Stock-Consumer Staples | 0.84% | +0.03% | -12.48% | |
| 15 | P | Everpure Inc-a | Stock-Tech | 0.82% | +0.26% | +19.92% | |
| 16 | APH | Amphenol Corp-cl A | Stock-Tech | 0.81% | +0.36% | +42.47% | |
| 17 | LIN | Linde plc | Stock-Materials | 0.79% | -0.25% | -20.65% | |
| 18 | ONTO | Onto Innovation Inc | Stock-Tech | 0.76% | +0.11% | -30.99% | |
| 19 | BWA | Borgwarner Inc | Stock-Consumer Disc | 0.76% | +0.24% | +31.23% | |
| 20 | CG | Carlyle Group Inc/the | Stock-Financials | 0.75% | -0.26% | -6.13% | |
| 21 | ARGX | Argenx Se - Adr | Stock-Healthcare | 0.74% | +0.10% | -0.55% | |
| 22 | MLI | Mueller Industries Inc | Stock-Industrials | 0.73% | -0.04% | -5.86% | |
| 23 | MNST | Monster Beverage CORP | Stock-Consumer Staples | 0.73% | +0.03% | -13.53% | |
| 24 | FFIV | F5 Inc | Stock-Tech | 0.73% | +0.11% | -9.80% | |
| 25 | BAP | Credicorp Ltd. | Stock-Financials | 0.73% | +0.03% | +0.39% | |
| 26 | CW | Curtiss-wright CORP | Stock-Industrials | 0.72% | +0.20% | +36.73% | |
| 27 | ITUB | Itau Unibanco H-spon Prf Adr | Stock-Financials | 0.69% | -0.19% | -10.73% | |
| 28 | SNOW | Snowflake Inc | Stock-Tech | 0.69% | +0.13% | -20.08% | |
| 29 | TWST | Twist Bioscience CORP | Stock-Other | 0.67% | -0.16% | -58.73% | |
| 30 | TEVA | Teva Pharmaceutical-sp Adr | Stock-Healthcare | 0.67% | +0.53% | +362.47% | |
| 31 | UNH | Unitedhealth Group Inc | Stock-Healthcare | 0.65% | +0.05% | -22.26% | |
| 32 | CRWD | Crowdstrike Holdings Inc - A | Stock-Tech | 0.65% | +0.65% | NEW | |
| 33 | RRX | Regal Rexnord CORP | Stock-Industrials | 0.64% | +0.12% | +6.41% | |
| 34 | KRYS | Krystal Biotech Inc | Stock-Healthcare | 0.64% | +0.29% | +40.03% | |
| 35 | CRS | Carpenter Technology | Stock-Industrials | 0.62% | +0.16% | -5.21% | |
| 36 | POWI | Power Integrations Inc | Stock-Tech | 0.60% | +0.20% | +0.06% | |
| 37 | NVT | nVent Electric plc | Stock-Industrials | 0.60% | +0.12% | -5.36% | |
| 38 | GH | Guardant Health Inc | Stock-Healthcare | 0.59% | +0.30% | +37.87% | |
| 39 | HALO | Halozyme Therapeutics Inc | Stock-Healthcare | 0.59% | +0.05% | -0.59% | |
| 40 | TLN | Talen Energy CORP | Stock-Utilities | 0.58% | +0.02% | -5.25% | |
| 41 | TRU | Transunion | Stock-Financials | 0.57% | -0.09% | -8.39% | |
| 42 | CCJ | Cameco CORP | Stock-Energy | 0.57% | -0.03% | +10.49% | |
| 43 | STRL | Sterling Infrastructure Inc | Stock-Industrials | 0.56% | +0.12% | -30.83% | |
| 44 | COST | Costco Wholesale CORP | Stock-Consumer Staples | 0.56% | -0.44% | -34.09% | |
| 45 | ALHC | Alignment Healthcare Inc | Stock-Other | 0.56% | +0.26% | +48.84% | |
| 46 | CHRW | C.h. Robinson Worldwide Inc | Stock-Industrials | 0.55% | -0.02% | -6.08% | |
| 47 | STX | Seagate Technology Holdings plc | Stock-Tech | 0.55% | +0.55% | NEW | |
| 48 | DIOD | Diodes Inc | Stock-Other | 0.55% | +0.45% | +281.08% | |
| 49 | BWXT | Bwx Technologies Inc | Stock-Industrials | 0.55% | -0.11% | -4.13% | |
| 50 | AKAM | Akamai Technologies Inc | Stock-Tech | 0.55% | -0.06% | -5.16% |
1–50 of 200
Portfolio Performance
Performance for Q3 2026
+2.3%
Performance Last 4 Quarters
+14.2%
- Stdev
- +15.8%
- Beta
- +1.16
- Alpha
- -7.7%
- Max Drawdown
- -12.8%
- Annualized Perf
- +15.2%
- Batting Avg vs S&P
- +41.7%
- Sortino
- +1.82
- Stutzer
- +0.29
- Treynor
- +0.13
- Sterling
- +0.83
- Calmar
- +1.18
- Information Ratio
- -0.82
- Tracking Error
- +5.6%
- Stdev Down
- +8.5%
- Winning Months %
- +61.1%
- Losing Months %
- +38.9%
- Best 12 Months
- +33%
- Worst 12 Months
- -3.1%
- Efficiency Ratio
- +0.39
- Sharpe
- +0.97
- Stdev Sectors
- +10.9%
- Skewness
- +0.18
- Kurtosis
- -0.38
- Upside Potential
- +3.57
Reported value over time
Sector allocation
Sector allocation over time
Quarterly history
| Period | Holdings | Total value | Stability | Top holdings | |
|---|---|---|---|---|---|
| 2026 Q2 | 403 | $33.3B | 43 | ||
| 2026 Q1 | 413 | $30.3B | 43 | ||
| 2025 Q4 | 413 | $35.9B | 30 | ||
| 2025 Q3 | 414 | $38.7B | 49 | ||
| 2025 Q2 | 417 | $37.7B | 0 | ||
| 2025 Q1 | 423 | $35.6B | 100 | ||
| 2024 Q4 | 433 | $40.9B | 0 | ||
| 2024 Q3 | 412 | $40.5B | 0 | ||
| 2024 Q2 | 411 | $38.1B | 0 | ||
| 2024 Q1 | 410 | $38.7B | 0 | ||
| 2023 Q4 | 406 | $34.4B | 0 | ||
| 2023 Q3 | 398 | $30.1B | 0 | ||
| 2023 Q2 | 395 | $31.2B | 0 | ||
| 2023 Q1 | 393 | $28.7B | 0 | ||
| 2022 Q4 | 401 | $26.1B | 0 | ||
| 2022 Q3 | 387 | $25.3B | 0 | ||
| 2022 Q2 | 403 | $27.0B | 0 | ||
| 2022 Q1 | 441 | $33.5B | 0 | ||
| 2021 Q4 | 427 | $37.0B | 0 | ||
| 2021 Q3 | 431 | $35.5B | 0 | ||
| 2021 Q2 | 465 | $31.9B | 100 | ||
| 2021 Q1 | 367 | $30.9B | 26 | ||
| 2020 Q4 | 356 | $30.0B | 30 | ||
| 2020 Q3 | 343 | $25.7B | 24 | ||
| 2020 Q2 | 341 | $24.6B | 40 | ||
| 2020 Q1 | 339 | $20.5B | 40 | ||
| 2019 Q4 | 356 | $25.1B | 25 | ||
| 2019 Q3 | 357 | $23.4B | 24 | ||
| 2019 Q2 | 372 | $23.8B | 29 | ||
| 2019 Q1 | 406 | $23.8B | 29 | ||
| 2018 Q4 | 404 | $20.1B | 49 | ||
| 2018 Q3 | 419 | $28.9B | 26 | ||
| 2018 Q2 | 476 | $26.9B | 30 | ||
| 2018 Q1 | 432 | $26.2B | 32 | ||
| 2017 Q4 | 427 | $25.7B | 32 | ||
| 2017 Q3 | 434 | $27.9B | 25 | ||
| 2017 Q2 | 448 | $27.5B | 25 | ||
| 2017 Q1 | 433 | $26.5B | 32 | ||
| 2016 Q4 | 435 | $25.0B | 35 | ||
| 2016 Q3 | 443 | $26.4B | 30 | ||
| 2016 Q2 | 451 | $25.3B | 29 | ||
| 2016 Q1 | 450 | $25.2B | 35 | ||
| 2015 Q4 | 444 | $24.7B | 100 | ||
| 2015 Q3 | 1068 | $49.0B | — |
* This report is exclusively curated by the AlphaSMO team. AlphaSMO is the web's most authoritative 13F / Inside Trader database, delivering precise insider trading and institutional holdings insights.
Holding changes this quarter
William Blair Investment Management, LLC's most significant position changes for 2026-06-30: New buy: General Electric (GE); New buy: Crowdstrike Holdings Inc - A (CRWD); New buy: Seagate Technology Holdings plc (STX); Sold out: Coherent CORP (COHR); New buy: Canadian Natural Resources (CNQ).
Showing top 200 changes by size (of 460 total)
| # | Ticker | Issuer | Weight Change | Shares Change | Action |
|---|---|---|---|---|---|
| 1 | GOOGL | Alphabet Inc-cl A | +1.1% | +27.41% | Add |
| 2 | AMAT | Applied Materials Inc | +1% | +1325.15% | Add |
| 3 | TSM | Taiwan Semiconductor-sp Adr | +0.9% | -10.54% | Trim |
| 4 | GE | General Electric | +0.9% | NEW | New buy |
| 5 | CRWD | Crowdstrike Holdings Inc - A | +0.7% | NEW | New buy |
| 6 | AMD | Advanced Micro Devices | +0.6% | -26.77% | Trim |
| 7 | STX | Seagate Technology Holdings plc | +0.6% | NEW | New buy |
| 8 | TEVA | Teva Pharmaceutical-sp Adr | +0.5% | +362.47% | Add |
| 9 | DIOD | Diodes Inc | +0.5% | +281.08% | Add |
| 10 | CNQ | Canadian Natural Resources | +0.4% | NEW | New buy |
| 11 | FPS | Forgent Power Solutions Inc | +0.4% | NEW | New buy |
| 12 | PTCT | Ptc Therapeutics Inc | +0.4% | NEW | New buy |
| 13 | WST | West Pharmaceutical Services | +0.4% | +950.49% | Add |
| 14 | TKR | Timken Co | +0.4% | +18347.43% | Add |
| 15 | MIRM | Mirum Pharmaceuticals Inc | +0.4% | +318.49% | Add |
| 16 | APH | Amphenol Corp-cl A | +0.4% | +42.47% | Add |
| 17 | ETSY | Etsy Inc | +0.4% | NEW | New buy |
| 18 | RGEN | Repligen CORP | +0.3% | NEW | New buy |
| 19 | GH | Guardant Health Inc | +0.3% | +37.87% | Add |
| 20 | HBM | Hudbay Minerals Inc | +0.3% | NEW | New buy |
| 21 | KRYS | Krystal Biotech Inc | +0.3% | +40.03% | Add |
| 22 | JAZZ | Jazz Pharmaceuticals plc | +0.3% | +516.36% | Add |
| 23 | P | Everpure Inc-a | +0.3% | +19.92% | Add |
| 24 | ALHC | Alignment Healthcare Inc | +0.3% | +48.84% | Add |
| 25 | MAR | Marriott International -cl A | +0.3% | +255.51% | Add |
| 26 | BWA | Borgwarner Inc | +0.2% | +31.23% | Add |
| 27 | AAOI | Applied Optoelectronics Inc | +0.2% | NEW | New buy |
| 28 | LRN | Stride Inc | +0.2% | NEW | New buy |
| 29 | CW | Curtiss-wright CORP | +0.2% | +36.73% | Add |
| 30 | POWI | Power Integrations Inc | +0.2% | +0.06% | Add |
| 31 | TXN | Texas Instruments Inc | +0.2% | +19.34% | Add |
| 32 | ✓ | +0.2% | NEW | New buy | |
| 33 | CYTK | Cytokinetics Inc | +0.2% | +47.43% | Add |
| 34 | TTE | TotalEnergies SE | +0.2% | +113.09% | Add |
| 35 | CRS | Carpenter Technology | +0.2% | -5.21% | Trim |
| 36 | CRCL | Circle Internet Group Inc | +0.2% | NEW | New buy |
| 37 | AMX | America Movil Sab De Cv | +0.2% | NEW | New buy |
| 38 | KRMN | Karman Holdings Inc | +0.2% | NEW | New buy |
| 39 | BSY | Bentley Systems Inc-class B | +0.1% | +78.84% | Add |
| 40 | VCYT | Veracyte Inc | +0.1% | +44.65% | Add |
| 41 | SNOW | Snowflake Inc | +0.1% | -20.08% | Trim |
| 42 | SAIA | Saia Inc | +0.1% | +52.23% | Add |
| 43 | KNX | Knight-swift Transportation | +0.1% | +41.00% | Add |
| 44 | WFRD | Weatherford International plc | +0.1% | +117.42% | Add |
| 45 | VSH | Vishay Intertechnology Inc | +0.1% | -18.44% | Trim |
| 46 | WGS | Genedx Holdings CORP | +0.1% | +80.67% | Add |
| 47 | JBTM | Jbt Marel CORP | +0.1% | +176.82% | Add |
| 48 | PSMT | Pricesmart Inc | +0.1% | +413.53% | Add |
| 49 | STRL | Sterling Infrastructure Inc | +0.1% | -30.83% | Trim |
| 50 | RRX | Regal Rexnord CORP | +0.1% | +6.41% | Add |
1–50 of 200
Filing History
FAQ
What is William Blair Investment Management, LLC and what type of investor is it?
William Blair Investment Management, LLC is an investment manager that files SEC Form 13F quarterly, disclosing its U.S. public equity holdings to regulators. As of the most recent reporting period (2026-06-30), the firm manages a tracked equity portfolio valued at approximately $33.3B, spread across 403 disclosed positions.
What are William Blair Investment Management, LLC's largest equity positions?
Based on the latest 13F filing, William Blair Investment Management, LLC's top holdings by market value are:
1. Taiwan Semiconductor-sp Adr (TSM) — $2.4B (7.1%)
2. Nvidia CORP (NVDA) — $1.7B (5.2%)
3. Alphabet Inc-cl A (GOOGL) — $1.1B (3.4%)
4. Apple Inc (AAPL) — $943.3M (2.8%)
5. Broadcom Inc (AVGO) — $776.7M (2.3%)
What changes did William Blair Investment Management, LLC make in its most recent portfolio filing?
In the latest reported quarter, William Blair Investment Management, LLC made 200 notable position adjustments: 31 new positions were initiated, 58 existing holdings were added to, 81 positions were partially reduced, and 30 were completely exited. The largest of these moves: New buy: General Electric (GE); New buy: Crowdstrike Holdings Inc - A (CRWD); New buy: Seagate Technology Holdings plc (STX); Sold out: Coherent CORP (COHR); New buy: Canadian Natural Resources (CNQ)
What sectors does William Blair Investment Management, LLC focus on?
William Blair Investment Management, LLC is concentrated in the following sectors based on its current disclosed equity portfolio:
• Information Technology: 41.2%
• Industrials: 12.8%
• Health Care: 12.4%
• Financials: 8.7%
• Consumer Discretionary: 8.2%
• Communication Services: 6.4%
Investment Profile
William Blair Investment Management, LLC returned an annualized 15.2% over the trailing 36 months — underperforming the S&P 500 by 7.7 points — based on a reconstructed track record of its disclosed 13F positions, with a beta of 1.16 (more volatile than the market) and a 42% quarterly batting average against the index.
Its portfolio is broadly diversified and moderately active, with 41.2% of the portfolio concentrated in Information Technology.
Its turnover score has risen from 0 to 43 over the past 4 quarters — a shift toward more active trading.
It has added to its TSM position over the past two quarters (+$538.7M, now $2.4B), while trimming MSFT over the same stretch (-$923.8M, still holding $764.2M).
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Developer Access
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