SEI Investments Company
US ˙ NasdaqGS ˙ US7841171033

SecuritySEIC / SEI Investments Company
InstitutionState Street Corp
Latest Disclosed Ownership4,185,178 shares
Latest Disclosed Value $ 328,410,918
State Street Corp reports 2.29% decrease in ownership of SEIC / SEI Investments Company

On May 15, 2026 - State Street Corp filed a 13F-HR form disclosing ownership of 4,185,178 shares of SEI Investments Company (US:SEIC) valued at $328,410,918 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 4,283,065 shares of SEI Investments Company. This represents a change in shares of -2.29% during the quarter. The current value of the position is $370,723,067 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F SEI INVTS COM 784117103 4,185,178 -97,887 -2.29 328,411 -7.10 0.0113
2026-02-13 2025-12-31 13F SEI INVTS COM 784117103 4,283,065 -253,517 -5.59 353,493 -8.17 0.0119
2025-11-14 2025-09-30 13F SEI INVTS COM 784117103 4,536,582 -208,903 -4.40 384,929 -9.73 0.0133
2025-08-14 2025-06-30 13F SEI INVTS COM 784117103 4,745,485 -992,326 -17.29 426,429 -4.26 0.0160
2025-05-15 2025-03-31 13F SEI INVTS COM 784117103 5,737,811 55,158 0.97 445,426 -5.52 0.0184
2025-02-14 2024-12-31 13F SEI INVTS COM 784117103 5,682,653 -25,349 -0.44 471,452 19.37 0.0186
2024-11-14 2024-09-30 13F SEI INVTS COM 784117103 5,708,002 -403,318 -6.60 394,937 -0.10 0.0161
2024-08-14 2024-06-30 13F SEI INVTS COM 784117103 6,111,320 289,228 4.97 395,341 -5.56 0.0173
2024-05-15 2024-03-31 13F SEI INVTS COM 784117103 5,822,092 -129,799 -2.18 418,608 9.89 0.0187
2024-02-14 2023-12-31 13F SEI INVTS COM 784117103 5,951,891 155,520 2.68 380,918 9.11 0.0185
2023-11-14 2023-09-30 13F SEI INVTS COM 784117103 5,796,371 -382,381 -6.19 349,115 -5.23 0.0194
2023-08-14 2023-06-30 13F SEI INVTS COM 784117103 6,178,752 59,268 0.97 368,377 4.60 0.0193
2023-05-15 2023-03-31 13F SEI INVTS COM 784117103 6,119,484 -586,595 -8.75 352,176 -10.56 0.0199
2023-05-15 2022-12-31 13F/A-99 SEI INVTS COM 784117103 6,706,079 412,456 6.55 393,748 27.55 0.0231
2023-05-15 2022-12-31 13F SEI INVTS COM 784117103 6,706,079 412,456 393,748 0.0231
2022-11-15 2022-09-30 13F SEI INVTS COM 784117103 6,293,623 52,265 0.84 308,702 -8.44 0.0195
2022-08-15 2022-06-30 13F SEI INVTS COM 784117103 6,241,358 98,309 1.60 337,158 -8.84 0.0202
2022-05-16 2022-03-31 13F SEI INVTS COM 784117103 6,143,049 452,434 7.95 369,873 5.97 0.0183
2022-02-14 2021-12-31 13F SEI INVTS COM 784117103 5,690,615 35,910 0.64 349,030 4.09 0.0166
2021-11-15 2021-09-30 13F SEI INVTS COM 784117103 5,654,705 -256,609 -4.34 335,324 -8.46 0.0177
2021-08-16 2021-06-30 13F SEI INVTS COM 784117103 5,911,314 482,019 8.88 366,324 10.74 0.0193
2021-07-09 2021-03-31 13F/A-1 SEI INVTS COM 784117103 5,429,295 -45,082 -0.82 330,807 4.47 0.0190
2021-05-17 2021-03-31 13F SEI INVTS COM 784117103 5,429,295 -45,082 330,807 0.0190
2021-02-16 2020-12-31 13F SEI INVTS COM 784117103 5,474,377 115,054 2.15 316,639 16.49 0.0194
2020-11-10 2020-09-30 13F SEI INVTS COM 784117103 5,359,323 -312,714 -5.51 271,825 -12.83 0.0186
2020-08-14 2020-06-30 13F SEI INVTS COM 784117103 5,672,037 -196,322 -3.35 311,849 14.68 0.0227
2020-06-19 2020-03-31 13F/A-1 SEI INVESTMENTS COM 784117103 5,868,359 -304,228 -4.93 271,940 -33.07 0.0238
2020-05-11 2020-03-31 13F SEI INVESTMENTS COM 784117103 5,868,359 -304,228 271,940 23,881.8076
2020-02-06 2019-12-31 13F SEI INVESTMENTS COM 784117103 6,172,587 -125,867 -2.00 406,326 8.87 0.0278
2019-11-14 2019-09-30 13F SEI INVESTMENTS COM 784117103 6,298,454 -112,412 -1.75 373,215 3.77 0.0278
2019-08-14 2019-06-30 13F SEI INVESTMENTS COM 784117103 6,410,866 -114,475 -1.75 359,650 5.48 0.0268
2019-05-15 2019-03-31 13F SEI INVESTMENTS COM 784117103 6,525,341 791,289 13.80 340,949 27.81 0.0266
2019-02-12 2018-12-31 13F SEI INVESTMENTS COM 784117103 5,734,052 133,871 2.39 266,772 -22.04 0.0243
2018-11-09 2018-09-30 13F SEI INVESTMENTS Common equity shares 784117103 5,600,181 580,132 11.56 342,171 9.02 0.0263
2018-08-14 2018-06-30 13F SEI INVESTMENTS Common equity shares 784117103 5,020,049 -337,329 -6.30 313,853 -21.79 0.0262
2018-05-15 2018-03-31 13F SEI INVESTMENTS Common equity shares 784117103 5,357,378 -332,442 -5.84 401,316 -1.85 0.0341
2018-02-14 2017-12-31 13F SEI INVESTMENTS Common equity shares 784117103 5,689,820 -128,513 -2.21 408,873 15.09 0.0329
2017-11-14 2017-09-30 13F SEI INVESTMENTS Common equity shares 784117103 5,818,333 -136,659 -2.29 355,275 10.94 0.0307
2017-08-14 2017-06-30 13F SEI INVESTMENTS Common equity shares 784117103 5,954,992 21,421 0.36 320,254 7.01 0.0283
2017-05-15 2017-03-31 13F SEI INVESTMENTS Common equity shares 784117103 5,933,571 -16,820 -0.28 299,283 1.90 0.0267
2017-02-09 2016-12-31 13F SEI INVESTMENTS Common equity shares 784117103 5,950,391 94,471 1.61 293,716 9.97 0.0276
2017-01-13 2016-09-30 13F/A-1 SEI INVESTMENTS Common equity shares 784117103 5,855,920 -17,525 -0.30 267,087 -5.48 0.0269
2016-11-14 2016-09-30 13F SEI INVESTMENTS Common equity shares 784117103 5,842,733 266,485
2016-08-12 2016-06-30 13F SEI INVESTMENTS Common equity shares 784117103 5,873,445 294,819 5.28 282,569 17.66 0.0304
2016-05-20 2016-03-31 13F/A-1 SEI INVESTMENTS Common equity shares 784117103 5,578,626 -17,880 -0.32 240,163 -18.10 0.0260
2016-05-12 2016-03-31 13F SEI INVESTMENTS Common equity shares 784117103 5,578,626 240,163
2016-02-16 2015-12-31 13F SEI INVESTMENTS Common equity shares 784117103 5,596,506 43,590 0.78 293,252 9.50 0.0321
2015-11-16 2015-09-30 13F SEI INVESTMENTS Common equity shares 784117103 5,552,916 -505,881 -8.35 267,819 -9.84 0.0312
2015-08-13 2015-06-30 13F SEI INVESTMENTS Common equity shares 784117103 6,058,797 -798,498 -11.64 297,061 -1.74 0.0318
2015-05-15 2015-03-31 13F SEI INVESTMENTS Common equity shares 784117103 6,857,295 -242,984 -3.42 302,325 6.35 0.0310
2015-02-11 2014-12-31 13F SEI INVESTMENTS Common equity shares 784117103 7,100,279 -527,157 -6.91 284,285 3.07 0.0283
2014-11-12 2014-09-30 13F/A-1 SEI INVESTMENTS Common equity shares 784117103 7,627,436 -205,767 -2.63 275,805 7.44 0.0297
2014-11-10 2014-09-30 13F SEI INVESTMENTS Common equity shares 784117103 7,627,436 275,805
2014-08-12 2014-06-30 13F SEI INVESTMENTS Common equity shares 784117103 7,833,203 163,379 2.13 256,699 -0.42 0.0277
2014-05-15 2014-03-31 13F/A-1 SEI INVESTMENTS Common equity shares 784117103 7,669,824 -435,446 -5.37 257,782 -8.43 0.0293
2014-05-13 2014-03-31 13F SEI INVESTMENTS Common equity shares 784117103 7,671,420 257,836
2014-02-06 2013-12-31 13F/A-1 SEI INVESTMENTS Common equity shares 784117103 8,105,270 -410,484 -4.82 281,500 6.94 0.0313
2014-02-06 2013-12-31 13F SEI INVESTMENTS Common equity shares 784117103 8,426,851 196,684
2013-11-12 2013-09-30 13F SEI INVESTMENTS Common equity shares 784117103 8,515,754 682,593 8.71 263,222 18.20 0.0324
2013-08-08 2013-06-30 13F SEI INVESTMENTS Common equity shares 784117103 7,833,161 7,833,161 222,699 0.0290
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.