Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
267 institutional managers reported holding SIMO for the quarter ended Mar 31, 2026. Together they hold about 20% of shares outstanding; the top 10 hold 8%. 60 opened new positions; 32 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| FMR (Fidelity) | 3.40M | 2.52% | $382.0M | unchanged | 2015 Q3 |
| Reinhart Partners, LLC. | 1.31M | 0.97% | $147.7M | trimmed -16.5% | 2023 Q3 |
| Acadian Asset Management | 1.29M | 0.96% | $145.4M | added +1.1% | 2019 Q4 |
| Hawk Ridge Capital Management LP (focused) | 1.17M | 0.87% | $131.9M | added +48.9% | 2023 Q1 |
| Lord, Abbett & CO. LLC | 962.1k | 0.71% | $108.1M | trimmed -3.3% | 2024 Q1 |
| Lazard Asset Management LLC | 782.0k | 0.58% | $87.9M | added +3.1% | 2014 Q2 |
| Robeco Institutional Asset Management B.v. | 631.6k | 0.47% | $71.0M | added +1.2% | 2022 Q4 |
| Wolf Hill Capital Management, LP (focused) | 580.9k | 0.43% | $65.3M | unchanged | 2025 Q4 |
| Man Group | 560.1k | 0.42% | $63.0M | added +47% | 2025 Q3 |
| Analog Century Management LP (focused) | 538.7k | 0.40% | $60.6M | opened | 2026 Q1 |
| Driehaus Capital Management LLC | 510.0k | 0.38% | $57.3M | added +59.6% | 2025 Q2 |
| Systematic Financial Management LP | 506.7k | 0.38% | $57.0M | trimmed -13.1% | ≤2013 |
| Summit Partners Public Asset Management, LLC | 456.4k | 0.34% | $51.3M | trimmed -14.7% | 2023 Q4 |
| Kite Lake Capital Management (UK) LLP (focused) | 452.6k | 0.34% | $50.9M | trimmed -0.8% | 2024 Q3 |
| Highland Peak Capital, LLC (focused) | 444.5k | 0.33% | $50.0M | trimmed -10.5% | 2025 Q2 |
| Neumeier Poma Investment Counsel LLC (focused) | 428.2k | 0.32% | $48.1M | trimmed -11.1% | 2024 Q2 |
| Arrowstreet Capital | 425.7k | 0.32% | $47.8M | added +112.3% | 2025 Q2 |
| Invesco | 418.3k | 0.31% | $47.0M | trimmed -33.8% | 2023 Q3 |
| Pertento Partners LLP (focused) | 412.5k | 0.31% | $46.4M | trimmed -64.2% | 2023 Q3 |
| Millennium Management | 395.8k | 0.29% | $44.5M | added +169.2% | ≤2013 |
| UBS | 392.5k | 0.29% | $44.1M | added +11.6% | ≤2013 |
| Voya Investment Management LLC | 381.9k | 0.28% | $42.9M | opened | 2026 Q1 |
| Herald Investment Management LTD | 367.7k | 0.27% | $41.3M | trimmed -4.5% | ≤2013 |
| Ophir Asset Management Pty LTD (focused) | 357.0k | 0.27% | $40.1M | trimmed -23.6% | 2025 Q2 |
| Qube Research & Technologies LTD | 351.5k | 0.26% | $39.5M | added +268.5% | 2025 Q4 |
| CastleKnight Management LP | 323.5k | 0.24% | $36.4M | added +293.3% | 2025 Q4 |
| Wellington Management | 304.3k | 0.23% | $34.2M | trimmed -56.3% | 2015 Q2 |
| Schwartz Investment Counsel INC | 300.0k | 0.22% | $33.7M | added +36.4% | 2024 Q1 |
| Oberweis Asset Management INC/ | 282.6k | 0.21% | $31.8M | added +19.6% | 2023 Q4 |
| Marshall Wace | 276.6k | 0.20% | $31.1M | added +108.5% | 2016 Q4 |
| Two Sigma | 274.6k | 0.20% | $30.9M | trimmed -27.7% | 2016 Q3 |
| Boston Partners | 272.8k | 0.20% | $30.7M | trimmed -28.9% | 2023 Q4 |
| Frontier Capital Management CO LLC | 272.4k | 0.20% | $30.6M | trimmed -46.8% | 2025 Q1 |
| Heartland Advisors INC | 252.1k | 0.19% | $28.3M | trimmed -7.5% | 2023 Q1 |
| Apis Capital Advisors, LLC | 249.2k | 0.18% | $28.0M | added +16.4% | 2024 Q2 |
| Bank OF America CORP /DE/ | 244.4k | 0.18% | $27.5M | added +33.2% | ≤2013 |
| Morgan Stanley | 211.0k | 0.16% | $23.7M | trimmed -20.3% | ≤2013 |
| Voloridge Investment Management | 210.3k | 0.16% | $23.6M | added +87% | 2025 Q4 |
| MFS Investment Management | 210.3k | 0.16% | $23.6M | added +1.7% | 2023 Q3 |
| Russell Investments Group, LTD. | 203.4k | 0.15% | $22.9M | added +2.3% | 2016 Q4 |
| Aigh Capital Management LLC (focused) | 200.0k | 0.15% | $22.5M | opened | 2026 Q1 |
| Granahan Investment Management, LLC | 195.3k | 0.14% | $21.9M | trimmed -14.8% | 2025 Q2 |
| Loomis Sayles & CO L P | 188.7k | 0.14% | $21.2M | opened | 2026 Q1 |
| Nomura Asset Management International INC. | 175.7k | 0.13% | $19.7M | added +61.1% | 2025 Q4 |
| First Eagle Investment Management | 168.4k | 0.13% | $18.9M | added +9.7% | 2025 Q2 |
| Fred Alger Management, LLC | 160.9k | 0.12% | $18.1M | opened | 2026 Q1 |
| Manufacturers Life Insurance Company, THE | 157.7k | 0.12% | $17.7M | trimmed -56.8% | 2024 Q1 |
| Bahl & Gaynor INC | 155.6k | 0.12% | $17.5M | opened | 2026 Q1 |
| Schroder Investment Management Group | 138.6k | 0.10% | $15.6M | added +267.4% | 2025 Q3 |
| Northern Trust | 125.0k | 0.09% | $14.0M | unchanged | 2024 Q1 |
Largest 50 of 267 shown; the full ranked, searchable register is at boothcheck.com/holders/SIMO. 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.