Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
597 institutional managers reported holding MKSI for the quarter ended Mar 31, 2026. Together they hold about 94% of shares outstanding; the top 10 hold 43%. 156 opened new positions; 59 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| Vanguard Group | 7.25M | 10.19% | $1.67B | trimmed -3.4% | ≤2013 |
| BlackRock | 6.64M | 9.34% | $1.53B | added +8.2% | ≤2013 |
| Invesco | 3.72M | 5.23% | $855.4M | trimmed -3.5% | ≤2013 |
| State Street | 2.06M | 2.89% | $473.0M | added +2% | ≤2013 |
| Capital International Investors | 1.97M | 2.77% | $452.5M | trimmed -39.2% | 2019 Q1 |
| FMR (Fidelity) | 1.93M | 2.72% | $444.5M | trimmed -39.5% | 2018 Q1 |
| Wellington Management | 1.83M | 2.58% | $421.4M | trimmed -28.2% | 2014 Q2 |
| T. Rowe Price | 1.70M | 2.39% | $390.8M | trimmed -38.3% | ≤2013 |
| Point72 | 1.61M | 2.27% | $370.1M | added +157.3% | 2024 Q2 |
| Geode Capital | 1.54M | 2.17% | $353.8M | added +22.7% | ≤2013 |
| Aspex Management (HK) LTD (focused) | 1.54M | 2.16% | $353.7M | opened | 2026 Q1 |
| Neuberger Berman Group LLC | 1.43M | 2.02% | $329.5M | trimmed -1.9% | 2015 Q3 |
| Whale Rock Capital (focused) | 1.31M | 1.84% | $300.4M | opened | 2026 Q1 |
| Capital Group (American Funds) | 1.28M | 1.80% | $293.6M | opened | 2026 Q1 |
| Westfield Capital Management CO LP | 1.05M | 1.47% | $240.6M | added +24.6% | 2025 Q3 |
| Citadel Advisors | 947.0k | 1.33% | $217.7M | added +106.8% | ≤2013 |
| Millennium Management | 894.4k | 1.26% | $205.6M | added +9.4% | 2023 Q3 |
| Victory Capital Management INC | 878.8k | 1.24% | $202.0M | trimmed -65.7% | 2013 Q3 |
| Charles Schwab Investment Management | 866.6k | 1.22% | $199.2M | unchanged | ≤2013 |
| Dimensional Fund Advisors | 835.3k | 1.18% | $192.0M | trimmed -25.2% | ≤2013 |
| BNY Mellon | 832.1k | 1.17% | $191.3M | added +5.5% | ≤2013 |
| UBS | 636.0k | 0.90% | $146.2M | added +21.4% | ≤2013 |
| AQR Capital | 616.5k | 0.87% | $141.7M | added +160.4% | ≤2013 |
| Principal Financial Group INC | 614.2k | 0.86% | $141.2M | trimmed -19.8% | ≤2013 |
| Northern Trust | 569.2k | 0.80% | $130.8M | added +0.6% | ≤2013 |
| Morgan Stanley | 515.1k | 0.72% | $118.4M | trimmed -12.8% | ≤2013 |
| Samlyn Capital, LLC | 496.7k | 0.70% | $114.2M | opened | 2026 Q1 |
| Franklin Resources | 475.9k | 0.67% | $109.4M | trimmed -54.3% | 2024 Q2 |
| Bank OF America CORP /DE/ | 463.7k | 0.65% | $106.6M | trimmed -3.4% | ≤2013 |
| FengHe Fund Management Pte. LTD. (focused) | 456.3k | 0.64% | $104.9M | opened | 2026 Q1 |
| Nomura Asset Management International INC. | 455.4k | 0.64% | $104.7M | trimmed -11.5% | 2024 Q1 |
| Balyasny Asset Management | 407.4k | 0.57% | $93.6M | trimmed -20.4% | 2022 Q4 |
| Royce & Associates | 403.7k | 0.57% | $92.8M | trimmed -34.5% | ≤2013 |
| Manufacturers Life Insurance Company, THE | 400.3k | 0.56% | $92.0M | trimmed -34% | ≤2013 |
| Nuveen | 378.2k | 0.53% | $86.9M | added +10.8% | ≤2013 |
| Blue Grotto Capital, LLC (focused) | 375.0k | 0.53% | $86.2M | trimmed -9.7% | 2024 Q1 |
| Contour Asset Management LLC (focused) | 374.9k | 0.53% | $86.2M | opened | 2026 Q1 |
| Madison Asset Management, LLC | 338.3k | 0.48% | $77.8M | trimmed -63.3% | 2021 Q4 |
| Raymond James Financial INC | 338.0k | 0.47% | $77.7M | added +35.5% | 2016 Q4 |
| Tremblant Capital Group | 329.8k | 0.46% | $75.8M | opened | 2026 Q1 |
| Nordea Investment Management AB | 326.3k | 0.46% | $75.0M | trimmed -45.6% | 2022 Q3 |
| AllianceBernstein | 319.9k | 0.45% | $73.5M | added +271.5% | ≤2013 |
| TimesSquare Capital Management, LLC | 288.2k | 0.41% | $66.2M | opened | 2026 Q1 |
| Summit Partners Public Asset Management, LLC | 282.2k | 0.40% | $64.9M | trimmed -26% | 2025 Q2 |
| American Century Companies INC | 281.0k | 0.40% | $64.6M | trimmed -29.3% | 2025 Q3 |
| Two Sigma | 278.7k | 0.39% | $64.1M | added +849.3% | 2021 Q3 |
| Quantinno Capital Management LP | 259.7k | 0.36% | $59.7M | added +12.5% | 2023 Q3 |
| Amundi | 254.7k | 0.36% | $58.6M | added +81.7% | 2018 Q1 |
| Defiance ETFs, LLC | 250.6k | 0.35% | $57.6M | added +5.3% | 2025 Q4 |
| Penserra Capital Management LLC | 250.6k | 0.35% | $57.6M | added +5.3% | 2017 Q4 |
Largest 50 of 597 shown; the full ranked, searchable register is at boothcheck.com/holders/MKSI. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.