SEI Investments Company
US ˙ NasdaqGS ˙ US7841171033

SecuritySEIC / SEI Investments Company
InstitutionJanus Henderson Group Plc
Latest Disclosed Ownership45,122 shares
Latest Disclosed Value $ 3,540,498
Janus Henderson Group Plc ownership in SEIC / SEI Investments Company

On May 18, 2026 - Janus Henderson Group Plc filed a 13F-HR/A form disclosing ownership of 45,122 shares of SEI Investments Company (US:SEIC) valued at $3,540,723 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 45,122 shares of SEI Investments Company. This represents a change in shares of 0.00% during the quarter. The current value of the position is $3,996,907 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)
2026-05-18 2026-03-31 13F/A-1 SEI INVTS COM 784117103 45,122 0 0.00 3,540 -4.32 0.0006
2026-05-15 2026-03-31 13F SEI INVTS COM 784117103 45,122 0 0.00 3,540 -4.32 0.0007
2026-02-17 2025-12-31 13F SEI INVTS COM 784117103 45,122 -978 -2.12 3,701 -5.40 0.0017
2025-11-14 2025-09-30 13F SEI INVTS COM 784117103 46,100 0 0.00 3,912 -5.58 0.0018
2025-08-14 2025-06-30 13F SEI INVTS COM 784117103 46,100 42,153 1,067.98 4,143 1,262.50 0.0020
2025-05-15 2025-03-31 13F SEI INVTS COM 784117103 3,947 0 0.00 304 -6.46 0.0002
2025-02-14 2024-12-31 13F SEI INVTS COM 784117103 3,947 0 0.00 326 19.05 0.0002
2024-11-14 2024-09-30 13F SEI INVTS COM 784117103 3,947 -3,400 -46.28 273 -42.53 0.0001
2024-08-14 2024-06-30 13F SEI INVTS COM 784117103 7,347 -517 -6.57 475 -15.93 0.0003
2024-05-15 2024-03-31 13F SEI INVTS COM 784117103 7,864 -743 -8.63 565 3.29 0.0003
2024-02-14 2023-12-31 13F SEI INVTS COM 784117103 8,607 -87 -1.00 547 4.59 0.0003
2023-11-14 2023-09-30 13F SEI INVTS COM 784117103 8,694 -5,718 -39.68 524 -39.12 0.0003
2023-08-14 2023-06-30 13F SEI INVTS COM 784117103 14,412 -2,003 -12.20 859 -9.00 0.0005
2023-05-15 2023-03-31 13F SEI INVTS COM 784117103 16,415 -7 -0.04 944 -1.26 0.0006
2023-02-14 2022-12-31 13F SEI INVTS COM 784117103 16,422 -2 -0.01 957 18.61 0.0007
2023-01-13 2022-09-30 13F/A-1 SEI INVTS COM 784117103 16,424 -2,926 -15.12 806 -22.94 0.0006
2022-11-14 2022-09-30 13F SEI INVTS COM 784117103 16,424 -2,926 806 0.0006
2022-08-15 2022-06-30 13F SEI INVTS COM 784117103 19,350 -28,881 -59.88 1,046 -63.98 0.0007
2022-05-16 2022-03-31 13F SEI INVTS COM 784117103 48,231 16,531 52.15 2,904 50.31 0.0014
2022-02-14 2021-12-31 13F SEI INVTS COM 784117103 31,700 -20,487 -39.26 1,932 -37.58 0.0008
2021-11-16 2021-09-30 13F SEI INVTS COM 784117103 52,187 -2,375 -4.35 3,095 -8.46 0.0014
2021-08-16 2021-06-30 13F SEI INVTS COM 784117103 54,562 6,930 14.55 3,381 16.43 0.0014
2021-05-17 2021-03-31 13F SEI INVTS COM 784117103 47,632 5,493 13.04 2,904 19.90 0.0013
2021-02-16 2020-12-31 13F SEI INVTS COM 784117103 42,139 3,379 8.72 2,422 23.26 0.0011
2020-11-16 2020-09-30 13F SEI INVTS COM 784117103 38,760 -81,281 -67.71 1,965 -70.23 0.0010
2020-08-14 2020-06-30 13F SEI INVTS COM 784117103 120,041 -206,976 -63.29 6,600 -56.45 0.0037
2020-05-14 2020-03-31 13F SEI INVESTMENTS COM 784117103 327,017 93,479 40.03 15,155 -0.90 0.0104
2020-02-18 2019-12-31 13F SEI INVESTMENTS COM 784117103 233,538 197,979 556.76 15,292 625.77 0.0078
2019-11-14 2019-09-30 13F SEI INVESTMENTS COM 784117103 35,559 0 0.00 2,107 5.56 0.0011
2019-07-31 2019-06-30 13F SEI INVESTMENTS COM 784117103 35,559 -1,432 -3.87 1,996 3.26 0.0011
2019-04-30 2019-03-31 13F SEI INVESTMENTS COM 784117103 36,991 -196,926 -84.19 1,933 -82.11 0.0011
2019-02-06 2018-12-31 13F SEI INVESTMENTS COM 784117103 233,917 -688,057 -74.63 10,807 -80.82 0.0069
2018-11-09 2018-09-30 13F SEI INVESTMENTS COM 784117103 921,974 -212,700 -18.75 56,333 -20.59 0.0301
2018-08-10 2018-06-30 13F SEI INVESTMENTS COM 784117103 1,134,674 268,000 30.92 70,940 9.27 0.0404
2018-05-14 2018-03-31 13F SEI INVESTMENTS COM 784117103 866,674 448,800 107.40 64,922 116.20 0.0383
2018-03-12 2017-12-31 13F/A-1 SEI INVESTMENTS COM 784117103 417,874 312,067 294.94 30,029 364.77 0.0185
2018-02-09 2017-12-31 13F SEI INVESTMENTS COM 784117103 417,874 312,067 30,029
2017-11-14 2017-09-30 13F SEI INVESTMENTS COM 784117103 105,807 -76,500 -41.96 6,461 -34.11 0.0041
2017-08-17 2017-06-30 13F/A-1 SEI INVESTMENTS COM 784117103 182,307 169,292 1,300.75 9,805 1,394.66 0.0067
2017-08-14 2017-06-30 13F SEI INVESTMENTS COM 784117103 182,307 169,292 9,805
2017-05-03 2017-03-31 13F SEI INVESTMENTS COM 784117103 13,015 0 0.00 656 2.02 0.0046
2017-01-30 2016-12-31 13F SEI INVESTMENTS COM 784117103 13,015 1,900 17.09 643 26.82 0.0047
2016-10-24 2016-09-30 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 507 -5.23 0.0037
2016-07-29 2016-06-30 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 535 11.69 0.0044
2016-05-12 2016-03-31 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 479 -17.70 0.0039
2016-02-03 2015-12-31 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 582 8.58 0.0047
2015-11-16 2015-09-30 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 536 -1.65 0.0047
2015-08-17 2015-06-30 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 545 11.22 0.0043
2015-06-02 2015-03-31 13F/A-1 SEI INVESTMENTS COM 784117103 11,115 0 0.00 490 10.11 0.0038
2015-05-15 2015-03-31 13F SEI INVESTMENTS COM 784117103 11,115 490
2015-02-12 2014-12-31 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 445 10.70 0.0032
2014-11-12 2014-09-30 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 402 10.44 0.0038
2014-08-13 2014-06-30 13F SEI INVESTMENTS COM 784117103 11,115 0 0.00 364 -2.67 0.0034
2014-05-08 2014-03-31 13F SEI INVESTMENTS COM 784117103 11,115 2,700 32.09 374 28.08 0.0036
2014-01-14 2013-12-31 13F SEI INVESTMENTS COM 784117103 8,415 0 0.00 292 12.31 0.0030
2013-11-12 2013-09-30 13F SEI INVESTMENTS COM 784117103 8,415 0 0.00 260 9.24 0.0029
2013-08-15 2013-06-30 13F SEI INVESTMENTS COM 784117103 8,415 8,415 238 0.0028
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.