Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
549 institutional managers reported holding SEIC for the quarter ended Mar 31, 2026. Together they hold about 73% of shares outstanding; the top 10 hold 41%. 70 opened new positions; 69 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| Vanguard Group | 11.64M | 9.35% | $912.9M | added +4.9% | ≤2013 |
| BlackRock | 10.11M | 8.12% | $792.7M | added +4.9% | ≤2013 |
| Loomis Sayles & CO L P | 8.63M | 6.93% | $676.5M | trimmed -1.3% | ≤2013 |
| Morgan Stanley | 4.79M | 3.85% | $375.7M | trimmed -5.6% | ≤2013 |
| State Street | 4.19M | 3.36% | $328.1M | trimmed -2.3% | ≤2013 |
| Bank OF America CORP /DE/ | 2.92M | 2.35% | $229.0M | unchanged | ≤2013 |
| Geode Capital | 2.83M | 2.27% | $221.9M | trimmed -2.2% | ≤2013 |
| Lord, Abbett & CO. LLC | 2.20M | 1.77% | $172.8M | added +15% | 2025 Q1 |
| FMR (Fidelity) | 2.09M | 1.68% | $164.1M | added +55.8% | ≤2013 |
| Dimensional Fund Advisors | 1.87M | 1.50% | $146.9M | added +1.1% | ≤2013 |
| First Trust Advisors LP | 1.82M | 1.46% | $142.9M | added +1.2% | 2019 Q1 |
| Beutel, Goodman & CO LTD. | 1.77M | 1.42% | $139.0M | trimmed -5.8% | 2020 Q2 |
| Boston Partners | 1.77M | 1.42% | $138.8M | opened | 2026 Q1 |
| Pacer Advisors, INC. | 1.33M | 1.06% | $104.0M | added +27.9% | 2020 Q3 |
| Caisse de depot et placement du Quebec | 1.20M | 0.96% | $93.9M | trimmed -13.2% | 2019 Q2 |
| Invesco | 1.15M | 0.92% | $89.8M | trimmed -33.9% | ≤2013 |
| Boston Trust Walden CORP | 1.04M | 0.83% | $81.5M | trimmed -4.2% | ≤2013 |
| Royce & Associates | 996.5k | 0.80% | $78.1M | added +9.9% | ≤2013 |
| Franklin Resources | 983.1k | 0.79% | $77.1M | added +20.1% | 2017 Q4 |
| BNY Mellon | 936.3k | 0.75% | $73.4M | trimmed -5.5% | ≤2013 |
| Northern Trust | 905.6k | 0.73% | $71.0M | added +1.6% | ≤2013 |
| Ameriprise Financial INC | 869.5k | 0.70% | $68.2M | added +5.9% | ≤2013 |
| Clark Capital Management Group, INC. | 837.8k | 0.67% | $65.7M | added +29.7% | 2024 Q4 |
| UBS | 772.5k | 0.62% | $60.6M | trimmed -29.1% | ≤2013 |
| American Capital Management INC | 768.6k | 0.62% | $60.3M | added +33.7% | ≤2013 |
| Charles Schwab Investment Management | 696.5k | 0.56% | $54.6M | added +4.8% | ≤2013 |
| Raymond James Financial INC | 572.2k | 0.46% | $44.9M | added +7.5% | ≤2013 |
| Arrowstreet Capital | 568.0k | 0.46% | $44.5M | added +22.5% | 2023 Q3 |
| First Financial Bankshares INC | 554.2k | 0.45% | $43.4M | opened | 2026 Q1 |
| PFA Pension, Forsikringsaktieselskab | 519.3k | 0.42% | $40.7M | unchanged | 2025 Q4 |
| Envestnet Asset Management INC | 498.5k | 0.40% | $39.1M | added +16.5% | ≤2013 |
| Natixis Advisors, LLC | 469.9k | 0.38% | $36.8M | unchanged | ≤2013 |
| Prana Capital Management, LP | 464.2k | 0.37% | $36.4M | trimmed -28.7% | 2023 Q3 |
| Victory Capital Management INC | 427.6k | 0.34% | $33.5M | added +11.7% | 2014 Q4 |
| AQR Capital | 420.0k | 0.34% | $32.9M | trimmed -7% | ≤2013 |
| Royal Bank OF Canada | 416.6k | 0.34% | $32.7M | trimmed -31.8% | ≤2013 |
| Voloridge Investment Management | 411.9k | 0.33% | $32.3M | added +8.9% | 2020 Q1 |
| Renaissance Technologies | 399.8k | 0.32% | $31.3M | added +0.7% | 2016 Q4 |
| Quantinno Capital Management LP | 382.4k | 0.31% | $30.0M | added +265.6% | 2023 Q2 |
| Barclays PLC | 381.0k | 0.31% | $29.9M | added +22.2% | ≤2013 |
| Man Group | 360.9k | 0.29% | $28.3M | added +8.2% | 2018 Q1 |
| Connor, Clark & Lunn Investment Management LTD. | 342.5k | 0.28% | $26.9M | added +67.7% | 2025 Q2 |
| Thrivent Financial for Lutherans | 325.6k | 0.26% | $25.5M | added +4.5% | ≤2013 |
| Goldman Sachs | 324.1k | 0.26% | $25.4M | added +1.5% | ≤2013 |
| Arbejdsmarkedets Tillaegspension | 323.4k | 0.26% | $25.4M | added +13.4% | 2025 Q4 |
| Rhumbline Advisers | 309.5k | 0.25% | $24.3M | unchanged | ≤2013 |
| ProShare Advisors LLC | 300.6k | 0.24% | $23.6M | trimmed -25.8% | ≤2013 |
| Retirement Systems of Alabama | 272.7k | 0.22% | $21.4M | trimmed -5.3% | ≤2013 |
| JLB & Associates INC | 259.2k | 0.21% | $20.3M | unchanged | ≤2013 |
| Bridgewater Associates | 232.7k | 0.19% | $18.2M | trimmed -32.7% | 2020 Q4 |
Largest 50 of 549 shown; the full ranked, searchable register is at boothcheck.com/holders/SEIC. 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.