Sei Investments SEIC Institutional Ownership

Updated Oct 5, 2026

Sei Investments Co (NASDAQ:SEIC) was held by 577 institutional investors that filed 13F reports for the quarter ended June 30, 2026.

• These investors held 75.77% of Sei Investments' outstanding shares at the end of Q2 2026, up from 73.98% in Q1 2026.
• Total holdings of SEIC shares rose 1.31% from Q1 2026, and the holder count rose 2.30% from Q2 2025.
• Among the 577 holders of Sei Investments, 256 added to their positions, 220 reduced their stakes and 101 left their positions unchanged.
• The aggregate institutional position in Sei Investments was 91.18Mn shares at the end of Q2 2026, up 1.18Mn from the prior quarter and up 6.99Mn from a year earlier.
• BlackRock, Inc. held the largest position in SEIC at 9.93Mn shares as of June 30, 2026, or 8.25% of shares outstanding.
• Holders that added the most shares of Sei Investments in Q2 2026 were Boston Partners (+1.32Mn shares), Jane Street Group, LLC (+572.5K shares), Barclays PLC (+444.24K shares), FMR LLC (+417.72K shares) and Quantinno Capital Management LP (+150.02K shares).
• Holders that trimmed the most shares of Sei Investments in Q2 2026 while keeping a position were Morgan Stanley (-673.08K shares), Franklin Templeton Inc (-470.29K shares), Prana Capital Management, LP (-325.02K shares), First Trust Advisors LP (-320.7K shares) and Ameriprise Financial Inc (-291.13K shares).
• Business Quant data shows the 10 biggest positions in Sei Investments as of Q2 2026 were held by BlackRock, Inc. (9.93Mn shares), Loomis Sayles & Co L.P. (8.48Mn shares), Vanguard Portfolio Management LLC (6.14Mn shares), Vanguard Capital Management LLC (4.69Mn shares), State Street Corp (4.25Mn shares), Morgan Stanley (4.12Mn shares), Boston Partners (3.09Mn shares), Geode Capital Management, LLC (2.95Mn shares), Bank of America Corp (2.91Mn shares) and FMR LLC (2.51Mn shares).