SEI Investments Company
US ˙ NasdaqGS ˙ US7841171033

SecuritySEIC / SEI Investments Company
InstitutionMarkel Corp
Latest Disclosed Ownership173,200 shares
Latest Disclosed Value $ 13,591,004
Markel Corp ownership in SEIC / SEI Investments Company

On May 1, 2026 - Markel Corp filed a 13F-HR form disclosing ownership of 173,200 shares of SEI Investments Company (US:SEIC) valued at $13,591,004 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 173,200 shares of SEI Investments Company. This represents a change in shares of 0.00% during the quarter. The current value of the position is $15,070,132 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)
2026-05-01 2026-03-31 13F SEI INVTS COM 784117103 173,200 0 0.00 13,591 -4.32 0.0982
2026-02-06 2025-12-31 13F SEI INVTS COM 784117103 173,200 0 0.00 14,206 -3.34 0.1132
2025-10-31 2025-09-30 13F SEI INVTS COM 784117103 173,200 0 0.00 14,696 -5.57 0.1193
2025-08-01 2025-06-30 13F SEI INVTS COM 784117103 173,200 0 0.00 15,564 15.75 0.1316
2025-05-02 2025-03-31 13F SEI INVTS COM 784117103 173,200 0 0.00 13,446 -5.88 0.1194
2025-02-07 2024-12-31 13F SEI INVTS COM 784117103 173,200 0 0.00 14,286 19.21 0.1259
2024-11-01 2024-09-30 13F SEI INVTS COM 784117103 173,200 0 0.00 11,984 6.95 0.1079
2024-08-02 2024-06-30 13F SEI INVTS COM 784117103 173,200 0 0.00 11,204 -10.03 0.1102
2024-05-03 2024-03-31 13F SEI INVTS COM 784117103 173,200 0 0.00 12,453 13.15 0.1228
2024-02-02 2023-12-31 13F SEI INVTS COM 784117103 173,200 0 0.00 11,007 5.51 0.1197
2023-11-03 2023-09-30 13F SEI INVTS COM 784117103 173,200 0 0.00 10,432 1.02 0.1259
2023-08-04 2023-06-30 13F SEI INVTS COM 784117103 173,200 -416,000 -70.60 10,326 -69.55 0.1229
2023-04-28 2023-03-31 13F SEI INVTS COM 784117103 589,200 0 0.00 33,908 -1.29 0.4314
2023-02-03 2022-12-31 13F SEI INVTS COM 784117103 589,200 30,000 5.36 34,350 25.23 0.4606
2022-11-04 2022-09-30 13F SEI INVTS COM 784117103 559,200 0 0.00 27,429 -9.20 0.4049
2022-08-05 2022-06-30 13F SEI INVTS COM 784117103 559,200 173,000 44.80 30,207 29.91 0.4319
2022-04-29 2022-03-31 13F SEI INVTS COM 784117103 386,200 -45,000 -10.44 23,253 -11.51 0.2581
2022-04-29 2022-03-31 13F SEI INVTS COM 784117103 445,200 26,805
2022-02-04 2021-12-31 13F SEI INVTS COM 784117103 431,200 0 0.00 26,277 2.76 0.3023
2021-11-05 2021-09-30 13F SEI INVTS COM 784117103 431,200 4,000 0.94 25,570 -3.41 0.3233
2021-08-06 2021-06-30 13F SEI INVTS COM 784117103 427,200 0 0.00 26,473 1.71 0.3351
2021-04-30 2021-03-31 13F SEI INVTS COM 784117103 427,200 1,000 0.23 26,029 6.27 0.3603
2021-02-05 2020-12-31 13F SEI INVTS COM 784117103 426,200 43,000 11.22 24,494 26.03 0.3649
2020-10-30 2020-09-30 13F SEI Investments COM 784117103 383,200 0 0.00 19,435 -7.76 0.3296
2020-08-03 2020-06-30 13F SEI Investments COM 784117103 383,200 0 0.00 21,069 18.65 0.3925
2020-05-01 2020-03-31 13F SEI Investments COM 784117103 383,200 0 0.00 17,757 -29.23 0.3340
2020-02-07 2019-12-31 13F SEI Investments COM 784117103 383,200 0 0.00 25,092 10.50 0.3484
2019-11-01 2019-09-30 13F SEI Investments COM 784117103 383,200 0 0.00 22,708 5.63 0.3431
2019-08-02 2019-06-30 13F SEI Investments COM 784117103 383,200 0 0.00 21,498 7.37 0.3305
2019-05-03 2019-03-31 13F SEI Investments COM 784117103 383,200 20,000 5.51 20,022 19.32 0.3356
2019-02-08 2018-12-31 13F SEI Investments COM 784117103 363,200 34,000 10.33 16,780 -16.58 0.3206
2018-11-02 2018-09-30 13F SEI Investments COM 784117103 329,200 23,000 7.51 20,114 5.07 0.3392
2018-08-03 2018-06-30 13F SEI Investments COM 784117103 306,200 0 0.00 19,144 -16.54 0.3514
2018-04-27 2018-03-31 13F SEI Investments COM 784117103 306,200 0 0.00 22,937 4.24 0.4360
2018-02-09 2017-12-31 13F SEI Investments COM 784117103 306,200 0 0.00 22,004 17.69 0.4154
2017-10-27 2017-09-30 13F SEI Investments COM 784117103 306,200 0 0.00 18,697 13.54 0.3723
2017-07-28 2017-06-30 13F SEI Investments COM 784117103 306,200 2,000 0.66 16,467 7.32 0.3512
2017-04-28 2017-03-31 13F SEI Investments COM 784117103 304,200 14,000 4.82 15,344 7.12 0.3457
2017-02-10 2016-12-31 13F SEI Investments COM 784117103 290,200 18,000 6.61 14,324 15.38 0.3452
2016-11-04 2016-09-30 13F SEI Investments COM 784117103 272,200 25,400 10.29 12,415 4.56 0.3200
2016-08-05 2016-06-30 13F SEI Investments COM 784117103 246,800 6,800 2.83 11,874 14.92 0.3129
2016-05-06 2016-03-31 13F SEI Investments COM 784117103 240,000 3,000 1.27 10,332 -16.80 0.2774
2016-02-16 2015-12-31 13F SEI Investments COM 784117103 237,000 0 0.00 12,419 8.64 0.3362
2015-11-09 2015-09-30 13F SEI Investments COM 784117103 237,000 0 0.00 11,431 -1.63 0.3011
2015-08-14 2015-06-30 13F SEI Investments COM 784117103 237,000 0 0.00 11,620 11.21 0.2902
2015-05-07 2015-03-31 13F SEI Investments COM 784117103 237,000 0 0.00 10,449 10.12 0.2641
2015-02-09 2014-12-31 13F SEI Investments COM 784117103 237,000 0 0.00 9,489 10.72 0.2504
2014-11-12 2014-09-30 13F SEI Investments COM 784117103 237,000 0 0.00 8,570 10.35 0.2417
2014-08-08 2014-06-30 13F SEI Investments COM 784117103 237,000 10,000 4.41 7,766 1.80 0.2214
2014-05-13 2014-03-31 13F SEI Investments COM 784117103 227,000 27,000 13.50 7,629 9.83 0.2342
2014-02-11 2013-12-31 13F SEI Investments COM 784117103 200,000 70,000 53.85 6,946 72.87 0.2195
2013-11-12 2013-09-30 13F SEI Investments COM 784117103 130,000 0 0.00 4,018 8.71 0.1378
2013-08-08 2013-06-30 13F SEI Investments COM 784117103 130,000 130,000 3,696 0.1322
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.