SEI Investments Company
US ˙ NasdaqGS ˙ US7841171033

SecuritySEIC / SEI Investments Company
InstitutionBoston Trust Walden Corp
Latest Disclosed Ownership1,039,731 shares
Latest Disclosed Value $ 81,587,687
Boston Trust Walden Corp reports 4.15% decrease in ownership of SEIC / SEI Investments Company

On April 24, 2026 - Boston Trust Walden Corp filed a 13F-HR form disclosing ownership of 1,039,731 shares of SEI Investments Company (US:SEIC) valued at $81,587,692 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 28, 2026 disclosing 1,084,790 shares of SEI Investments Company. This represents a change in shares of -4.15% during the quarter. The current value of the position is $90,466,994 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)
2026-04-24 2026-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,039,731 -45,059 -4.15 81,588 -8.30 0.4012
2026-01-28 2025-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,084,790 -20,619 -1.87 88,974 -5.14 0.6715
2025-10-17 2025-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,105,409 -264,265 -19.29 93,794 -23.79 0.6881
2025-07-28 2025-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,369,674 44,195 3.33 123,079 19.61 0.8779
2025-04-21 2025-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,325,479 19,150 1.47 102,897 -4.50 0.7518
2025-01-24 2024-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,306,329 20,020 1.56 107,746 21.06 0.7561
2024-10-24 2024-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,286,309 -10,033 -0.77 89,000 6.13 0.6192
2024-07-19 2024-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,296,342 -3,738 -0.29 83,860 -10.29 0.6220
2024-04-22 2024-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,300,080 -14,885 -1.13 93,476 11.86 0.6668
2024-01-24 2023-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,314,965 24,621 1.91 83,566 7.53 0.6304
2023-10-18 2023-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,290,344 -808 -0.06 77,717 0.96 0.6513
2023-07-24 2023-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,291,152 34,549 2.75 76,978 6.45 0.6313
2023-04-19 2023-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,256,603 -9,310 -0.74 72,318 -2.01 0.6242
2023-01-20 2022-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,265,913 80,817 6.82 73,803 26.96 0.6489
2022-10-19 2022-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,185,096 13,662 1.17 58,129 -8.14 0.5759
2022-07-22 2022-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 1,171,434 32,104 2.82 63,281 -7.75 0.5980
2022-04-20 2022-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 1,139,330 143,693 14.43 68,599 13.06 0.5666
2022-01-21 2021-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 995,637 106,556 11.98 60,674 15.08 0.4872
2021-10-25 2021-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 889,081 34,817 4.08 52,723 -0.41 0.4668
2021-07-22 2021-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 854,264 132,922 18.43 52,939 20.45 0.4707
2021-04-21 2021-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 721,342 114,297 18.83 43,952 25.98 0.4256
2021-01-15 2020-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 607,045 168,130 38.31 34,887 56.71 0.3722
2020-10-14 2020-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 438,915 -2,227 -0.50 22,262 -8.21 0.2773
2020-07-23 2020-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 441,142 37,603 9.32 24,254 29.70 0.3275
2020-04-24 2020-03-31 13F/A-1 SEI INVESTMENTS COMMON STOCK 784117103 403,539 -1,237 -0.31 18,700 -29.45 0.2980
2020-04-21 2020-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 403,539 -1,237 18,700 165,818.5682
2020-01-10 2019-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 404,776 9,672 2.45 26,505 13.22 0.3085
2019-10-21 2019-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 395,104 28,283 7.71 23,411 13.77 0.2943
2019-07-25 2019-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 366,821 35,283 10.64 20,578 18.79 0.2678
2019-04-16 2019-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 331,538 64,857 24.32 17,323 40.60 0.2358
2019-01-17 2018-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 266,681 85,631 47.30 12,321 11.38 0.1960
2018-10-23 2018-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 181,050 4,252 2.41 11,062 0.08 0.1524
2018-07-25 2018-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 176,798 10,857 6.54 11,053 -11.09 0.1622
2018-04-13 2018-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 165,941 -7 -0.00 12,431 4.24 0.1886
2018-01-29 2017-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 165,948 1,774 1.08 11,925 18.96 0.1748
2017-10-13 2017-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 164,174 1,814 1.12 10,024 14.80 0.1561
2017-07-19 2017-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 162,360 39,392 32.03 8,732 40.79 0.1403
2017-04-24 2017-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 122,968 -1,210 -0.97 6,202 1.17 0.0966
2017-02-07 2016-12-31 13F/A-1 SEI INVESTMENTS COMMON STOCK 784117103 124,178 4,206 3.51 6,130 12.02 0.0966
2017-02-01 2016-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 124,178 6,130
2016-10-17 2016-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 119,972 -1,573 -1.29 5,472 -6.43 0.0902
2016-08-09 2016-06-30 13F SEI INVESTMENTS COMMON STOCK 784117103 121,545 -19,772 -13.99 5,848 -3.86 0.0999
2016-04-19 2016-03-31 13F SEI INVESTMENTS COMMON STOCK 784117103 141,317 -35,690 -20.16 6,083 -34.42 0.1059
2016-01-21 2015-12-31 13F SEI INVESTMENTS COMMON STOCK 784117103 177,007 -23,925 -11.91 9,275 -4.29 0.1720
2015-10-29 2015-09-30 13F SEI INVESTMENTS COMMON STOCK 784117103 200,932 -2,084 -1.03 9,691 -2.64 0.1619
2015-07-17 2015-06-30 13F SEI INVTS COMMON STOCK 784117103 203,016 4,029 2.02 9,954 13.46 0.1518
2015-04-15 2015-03-31 13F SEI INVTS COMMON STOCK 784117103 198,987 198,987 0.00 8,773 0.1302
2015-01-28 2014-12-31 13F SEI INVTS COMMON STOCK 784117103 0 -207,644 -100.00 0 -100.00
2014-10-23 2014-09-30 13F SEI INVTS COMMON STOCK 784117103 207,644 -2,517 -1.20 7,509 9.03 0.1160
2014-08-01 2014-06-30 13F SEI INVTS COMMON STOCK 784117103 210,161 -949 -0.45 6,887 -2.95 0.1001
2014-04-11 2014-03-31 13F SEI INVTS COMMON STOCK 784117103 211,110 -104 -0.05 7,096 -3.26 0.1054
2014-02-11 2013-12-31 13F SEI INVTS COMMON STOCK 784117103 211,214 -337 -0.16 7,335 12.17 0.1070
2013-11-15 2013-09-30 13F SEI INVTS COMMON STOCK 784117103 211,551 1,973 0.94 6,539 9.75 0.1001
2013-08-08 2013-06-30 13F SEI INVTS COMMON STOCK 784117103 209,578 209,578 5,958 0.0962
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.