SEI Investments Company
MX ˙ BMV ˙ US7841171033
SecurityMX:SEIC / SEI Investments Company
InstitutionRobeco Institutional Asset Management B.V.
Latest Disclosed Ownership104,774 shares
Latest Disclosed Value $ 8,221,618
Robeco Institutional Asset Management B.V. reports 19.35% increase in ownership of SEIC / SEI Investments Company

On April 21, 2026 - Robeco Institutional Asset Management B.V. filed a 13F-HR form disclosing ownership of 104,774 shares of SEI Investments Company (MX:SEIC) valued at $8,221,618 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 23, 2026 disclosing 87,786 shares of SEI Investments Company. This represents a change in shares of 19.35% during the quarter.

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)
2026-04-21 2026-03-31 13F SEI INVTS COM 784117103 104,774 16,988 19.35 8,222 14.18 0.0117
2026-01-23 2025-12-31 13F SEI INVTS COM 784117103 87,786 -43,466 -33.12 7,200 -35.34 0.0103
2025-10-22 2025-09-30 13F SEI INVTS COM 784117103 131,252 54,067 70.05 11,137 60.58 0.0161
2025-07-18 2025-06-30 13F SEI INVTS COM 784117103 77,185 -24,920 -24.41 6,936 -12.50 0.0112
2025-04-23 2025-03-31 13F SEI INVTS COM 784117103 102,105 1,020 1.01 7,926 -4.93 0.0154
2025-01-23 2024-12-31 13F SEI INVTS COM 784117103 101,085 36,206 55.81 8,337 85.76 0.0158
2024-10-29 2024-09-30 13F SEI INVTS COM 784117103 64,879 -78,095 -54.62 4,489 -51.47 0.0089
2024-07-23 2024-06-30 13F SEI INVTS COM 784117103 142,974 29,107 25.56 9,249 12.96 0.0199
2024-04-24 2024-03-31 13F SEI INVTS COM 784117103 113,867 54,992 93.40 8,187 118.85 0.0178
2024-02-14 2023-12-31 13F/A-1 SEI INVTS COM 784117103 58,875 -14,581 -19.85 3,742 -15.44 0.0091
2024-02-08 2023-12-31 13F SEI INVTS COM 784117103 10,818 -62,638 59 0.0110
2023-10-24 2023-09-30 13F SEI INVTS COM 784117103 73,456 15,468 26.67 4,424 27.97 0.0118
2023-07-24 2023-06-30 13F SEI INVTS COM 784117103 57,988 -2,931 -4.81 3,457 -1.37 0.0091
2023-05-04 2023-03-31 13F SEI INVTS COM 784117103 60,919 2,134 3.63 3,506 2.28 0.0096
2023-02-07 2022-12-31 13F SEI INVTS COM 784117103 58,785 7,523 14.68 3,427 36.37 0.0099
2022-12-01 2022-09-30 13F/A-1 SEI INVTS COM 784117103 51,262 538 1.06 2,513 -8.25 0.0081
2022-10-27 2022-09-30 13F SEI INVTS COM 784117103 51,262 538 2,513 0.0080
2022-12-01 2022-06-30 13F/A-1 SEI INVTS COM 784117103 50,724 0 0.00 2,739 -10.31 0.0085
2022-07-27 2022-06-30 13F SEI INVTS COM 784117103 50,724 0 2,739 0.0084
2022-12-01 2022-03-31 13F/A-1 SEI INVTS COM 784117103 50,724 -62,482 -55.19 3,054 -55.73 0.0072
2022-04-26 2022-03-31 13F SEI INVTS COM 784117103 50,724 -62,482 3,054 0.0071
2022-12-01 2021-12-31 13F/A-1 SEI INVTS COM 784117103 113,206 -42,386 -27.24 6,899 -25.23 0.0147
2022-01-31 2021-12-31 13F SEI INVTS COM 784117103 113,206 -42,386 6,899 0.0145
2022-12-01 2021-09-30 13F/A-1 SEI INVTS COM 784117103 155,592 9,374 6.41 9,227 1.82 0.0205
2021-10-20 2021-09-30 13F SEI INVTS COM 784117103 155,592 9,374 9,227 0.0202
2022-12-01 2021-06-30 13F/A-1 SEI INVTS COM 784117103 146,218 28,003 23.69 9,062 25.81 0.0201
2021-07-28 2021-06-30 13F SEI INVTS COM 784117103 146,218 28,003 9,062 0.0198
2022-12-01 2021-03-31 13F/A-1 SEI INVTS COM 784117103 118,215 0 0.00 7,203 6.02 0.0178
2021-04-23 2021-03-31 13F SEI INVTS COM 784117103 118,215 0 7,203 0.0175
2022-12-01 2020-12-31 13F/A-1 SEI INVTS COM 784117103 118,215 -10,022 -7.82 6,794 4.46 0.0179
2021-01-28 2020-12-31 13F SEI INVTS COM 784117103 118,215 -10,022 6,794 0.0176
2021-01-19 2020-09-30 13F/A-1 SEI INVTS COM 784117103 128,237 5,948 4.86 6,504 -3.26 0.0201
2020-10-29 2020-09-30 13F SEI INVTS COM 784117103 128,237 5,948 6,504 20,086.4688
2021-01-19 2020-06-30 13F/A-1 SEI INVTS COM 784117103 122,289 30,791 33.65 6,723 58.56 0.0228
2020-07-20 2020-06-30 13F SEI INVTS COM 784117103 122,289 30,791 6,723 22,812.3382
2021-01-19 2020-03-31 13F/A-1 SEI INVESTMENTS COM 784117103 91,498 -7,143 -7.24 4,240 -34.37 0.0170
2020-04-30 2020-03-31 13F SEI INVESTMENTS COM 784117103 91,498 -7,143 4,240 16,994.8762
2021-01-19 2019-12-31 13F/A-1 SEI INVESTMENTS COM 784117103 98,641 33,396 51.19 6,460 67.10 0.0207
2020-02-06 2019-12-31 13F SEI INVESTMENTS COM 784117103 98,641 33,396 6,460 20,661.8132
2021-01-19 2019-09-30 13F/A-1 SEI INVESTMENTS COM 784117103 65,245 13,562 26.24 3,866 33.36 0.0136
2019-10-17 2019-09-30 13F SEI INVESTMENTS COM 784117103 65,245 13,562 3,866 13,629.2399
2021-01-19 2019-06-30 13F/A-1 SEI INVESTMENTS COM 784117103 51,683 -4,994 -8.81 2,899 -2.09 0.0102
2019-07-19 2019-06-30 13F SEI INVESTMENTS COM 784117103 51,683 -4,994 2,899 10,222.6323
2021-01-19 2019-03-31 13F/A-1 SEI INVESTMENTS COM 784117103 56,677 0 0.00 2,961 13.06 0.0109
2019-05-02 2019-03-31 13F SEI INVESTMENTS COM 784117103 56,677 0 2,961 10,871.7387
2021-01-19 2018-12-31 13F/A-1 SEI INVESTMENTS COM 784117103 56,677 0 0.00 2,619 -24.37 0.0118
2019-02-08 2018-12-31 13F SEI INVESTMENTS COM 784117103 56,677 0 2,619 11,739.5377
2021-01-19 2018-09-30 13F/A-1 SEI INVESTMENTS COM 784117103 56,677 -78,331 -58.02 3,463 -58.98 0.0137
2018-10-25 2018-09-30 13F SEI INVESTMENTS COM 784117103 56,677 56,677 3,463
2021-01-19 2018-06-30 13F/A-1 SEI INVESTMENTS COM 784117103 135,008 -100,161 -42.59 8,442 -52.08 0.0385
2021-01-19 2018-03-31 13F/A-1 SEI INVESTMENTS COM 784117103 235,169 173,357 280.46 17,617 296.60 0.0827
2018-05-07 2018-03-31 13F SEI INVESTMENTS COM 784117103 235,169 173,357 17,617 82,386.4681
2021-01-19 2017-12-31 13F/A-1 SEI INVESTMENTS COM 784117103 61,812 0 0.00 4,442 17.70 0.0230
2018-01-25 2017-12-31 13F SEI INVESTMENTS COM 784117103 61,812 0 4,442
2021-01-19 2017-09-30 13F/A-1 SEI INVESTMENTS COM 784117103 61,812 10,000 19.30 3,774 35.41 0.0234
2017-10-17 2017-09-30 13F SEI INVESTMENTS COM 784117103 61,812 10,000 3,774 23,381.2540
2021-01-19 2017-06-30 13F/A-1 SEI INVESTMENTS COM 784117103 51,812 0 0.00 2,787 6.62 0.0180
2017-08-07 2017-06-30 13F SEI INVESTMENTS COM 784117103 51,812 0 2,787 18,145.6146
2021-01-19 2017-03-31 13F/A-1 SEI INVESTMENTS COM 784117103 51,812 15,000 40.75 2,614 43.78 0.0174
2017-05-15 2017-03-31 13F SEI INVESTMENTS COM 784117103 51,812 15,000 2,614 17,362.0301
2017-02-09 2016-12-31 13F SEI INVESTMENTS COM 784117103 36,812 9,312 33.86 1,818 44.98 0.0142
2016-11-07 2016-09-30 13F SEI INVESTMENTS COM 784117103 27,500 0 0.00 1,254 -5.22 0.0093
2016-07-22 2016-06-30 13F SEI INVESTMENTS COM 784117103 27,500 -7,500 -21.43 1,323 -12.21 0.0100
2016-05-16 2016-03-31 13F SEI INVESTMENTS COM 784117103 35,000 10,000 40.00 1,507 15.04 0.0121
2016-02-08 2015-12-31 13F SEI INVESTMENTS COM 784117103 25,000 23,522 1,591.47 1,310 3,019.05 0.0112
2013-08-27 2013-06-30 13F SEI Investments COM 784117103 1,478 1,478 42 0.0004
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.