Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionSeizert Capital Partners, Llc
Latest Disclosed Ownership85,681 shares
Latest Disclosed Value $ 66,200,568
Seizert Capital Partners, Llc reports 9.53% decrease in ownership of REGN / Regeneron Pharmaceuticals, Inc.

On May 7, 2026 - Seizert Capital Partners, Llc filed a 13F-HR form disclosing ownership of 85,681 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $66,200,568 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 2, 2026 disclosing 94,705 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of -9.53% 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)
2026-05-07 2026-03-31 13F Regeneron Pharmaceuticals COM 75886F107 85,681 -9,024 -9.53 66,201 -9.44 3.0464
2026-02-02 2025-12-31 13F Regeneron Pharmaceuticals COM 75886F107 94,705 -4,085 -4.14 73,100 31.60 3.0877
2025-10-29 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 98,790 12,810 14.90 55,547 23.06 2.4066
2025-08-11 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 85,980 3,308 4.00 45,140 -13.91 1.9841
2025-05-08 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 82,672 28,368 52.24 52,433 35.55 2.4044
2025-02-06 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 54,304 8,529 18.63 38,682 -19.61 1.7469
2024-11-06 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 45,775 -6,185 -11.90 48,121 -11.89 2.1727
2024-08-07 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 51,960 -4,354 -7.73 54,612 0.76 2.7136
2024-05-01 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 56,314 543 0.97 54,202 10.65 2.4972
2024-02-07 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 55,771 -3,024 -5.14 48,983 1.24 2.4829
2023-11-06 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 58,795 1,323 2.30 48,386 17.17 2.5646
2023-07-27 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 57,472 -966 -1.65 41,296 -14.00 2.2146
2023-05-09 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 58,438 -4,288 -6.84 48,017 6.10 2.6419
2023-03-28 2022-12-31 13F/A-1 REGENERON PHARMACEUTICALS COM COM 75886F107 62,726 -8,752 -12.24 45,256 -8.09 2.4029
2023-01-30 2022-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 62,726 -8,752 45,256 2.3817
2022-11-02 2022-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 71,478 -13,823 -16.20 49,239 -2.35 2.7765
2022-08-04 2022-06-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 85,301 3,696 4.53 50,424 -11.53 2.6747
2022-05-03 2022-03-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 81,605 -5,757 -6.59 56,995 3.31 2.6179
2022-02-08 2021-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 87,362 -1,737 -1.95 55,171 2.32 2.4686
2021-11-03 2021-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 89,099 2,037 2.34 53,921 10.88 2.4693
2021-08-05 2021-06-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 87,062 2,485 2.94 48,628 21.52 2.3182
2021-05-05 2021-03-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 84,577 35,991 74.08 40,017 70.49 2.0887
2021-02-08 2020-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 48,586 12,852 35.97 23,472 17.34 1.3682
2020-11-03 2020-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 35,734 -711 -1.95 20,003 -11.99 1.3137
2020-08-06 2020-06-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 36,445 -4,033 -9.96 22,729 15.00 1.5403
2020-05-05 2020-03-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 40,478 -26,381 -39.46 19,765 -21.27 1.4552
2020-02-10 2019-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 66,859 -9,228 -12.13 25,104 18.94 1.2498
2019-11-07 2019-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 76,087 76,087 21,107 1.0637
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.