SEI Investments Co
SEIC- Exchange
- Nasdaq
- Industry
- Security Brokers, Dealers & Flotation Companies
- SEC CIK
- 0000350894
In the last 90 days, SEI Investments Co insiders filed 0 open-market purchases and 10 sales; 575 institutions reported holding it in 13F filings for Q2 2026, worth $7.94B in total; Markel Group is the only superinvestor holding it.
Holders of 5% or more of SEIC
Holders whose latest Schedule 13D or 13G filing reports 5% or more of SEI Investments Co, largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Loomis Sayles & Co L P | 13G/A | 7.10%8.68M shares | −0.09 ppfrom 7.19% | Nov 13, 20248 filings | May 14, 2026 | SEC |
| BlackRock, Inc. | 13G/A | 6.80%8.49M shares | – | Jul 16, 20251 filing | Jul 16, 2025 | SEC |
| Vanguard Portfolio Management LLC | 13G | 5.02%6.14M shares | New | Apr 29, 20261 filing | Apr 29, 2026 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
11 Schedule 13D and 13G filings on SEI Investments Co, newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| May 14, 20262:48 PM ET | Loomis Sayles & Co L P | 13G/A | 7.10%8.68M shares | −0.09 ppfrom 7.19% | Mar 31, 2026 | SEC |
| Apr 29, 20263:06 PM ET | Vanguard Portfolio Management LLC | 13G | 5.02%6.14M shares | New | Mar 31, 2026 | SEC |
| Mar 27, 20261:04 PM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | –Below 5% | Mar 13, 2026 | SEC |
| Feb 12, 20269:17 AM ET | Loomis Sayles & Co L P | 13G/A | 7.19%8.81M shares | −0.07 ppfrom 7.26% | Dec 31, 2025 | SEC |
| Nov 13, 20259:27 AM ET | Loomis Sayles & Co L P | 13G/A | 7.26%8.98M shares | +0.12 ppfrom 7.14% | Sep 30, 2025 | SEC |
| Aug 13, 20259:46 AM ET | Loomis Sayles & Co L P | 13G/A | 7.14%8.89M shares | +0.27 ppfrom 6.87% | Jun 30, 2025 | SEC |
| Jul 16, 20257:02 PM ET | BlackRock, Inc. | 13G/A | 6.80%8.49M shares | – | Jun 30, 2025 | SEC |
| May 15, 20259:36 AM ET | Loomis Sayles & Co L P | 13G/A | 6.87%8.72M shares | 0.00 ppfrom 6.87% | Mar 31, 2025 | SEC |
| Feb 12, 20259:35 AM ET | Loomis Sayles & Co L P | 13G/A | 6.87%8.86M shares | −0.18 ppfrom 7.05% | Dec 31, 2024 | SEC |
| Nov 14, 20244:09 PM ET | Loomis Sayles & Co L P | 13G/A | 7.05%9.15M shares | 0.00 ppfrom 7.05% | Sep 30, 2024 | SEC |
| Nov 13, 20249:36 AM ET | Loomis Sayles & Co L P | 13G/A | 7.05%9.15M shares | – | Sep 30, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell SEI Investments Co shares.
No Form 144 notices for SEI Investments Co are on file.