Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionBanco Santander, S.A.
Latest Disclosed Ownership40,590 shares
Latest Disclosed Value $ 31,361,458
Banco Santander, S.A. reports 7.57% increase in ownership of REGN / Regeneron Pharmaceuticals, Inc.

On May 8, 2026 - Banco Santander, S.A. filed a 13F-HR form disclosing ownership of 40,590 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $31,361,458 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 37,732 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of 7.57% 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)
2026-05-08 2026-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 40,590 2,858 7.57 31,361 7.68 0.1482
2026-02-13 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 37,732 -33,403 -46.96 29,124 -27.18 0.2181
2025-11-12 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 71,135 51,577 263.71 39,997 289.57 0.3551
2025-08-01 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 19,558 7,706 65.02 10,268 36.60 0.0975
2025-05-09 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 11,852 4,374 58.49 7,517 41.12 0.0830
2025-02-07 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 7,478 -220 -2.86 5,327 -34.18 0.0641
2024-11-12 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 7,698 127 1.68 8,092 1.70 0.0954
2024-07-29 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 7,571 126 1.69 7,957 11.05 0.0986
2024-05-10 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 7,445 -959 -11.41 7,166 -2.93 0.0864
2024-02-09 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 8,404 -677 -7.46 7,381 -1.23 0.0872
2023-11-08 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 9,081 -450 -4.72 7,473 9.13 0.1059
2023-08-14 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 9,531 -2,070 -17.84 6,848 -28.16 0.0898
2023-05-10 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 11,601 -1,089 -8.58 9,532 4.12 0.1427
2023-02-13 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 12,690 -4,084 -24.35 9,156 -20.78 0.1375
2022-11-08 2022-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 16,774 -96 -0.57 11,556 15.88 0.1542
2022-07-28 2022-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 16,870 -3,900 -18.78 9,972 -31.26 0.1329
2022-05-09 2022-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 20,770 2,370 12.88 14,506 24.84 0.1557
2022-02-09 2021-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 18,400 2,514 15.83 11,620 20.87 0.0626
2021-11-08 2021-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 15,886 -2,791 -14.94 9,614 -7.84 0.0517
2021-07-29 2021-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 18,677 727 4.05 10,432 22.85 0.0583
2021-05-10 2021-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 17,950 5,063 39.29 8,492 36.40 0.0598
2021-02-12 2020-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 12,887 2,378 22.63 6,226 5.83 0.0446
2020-11-09 2020-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 10,509 2,593 32.76 5,883 19.16 0.0774
2020-08-05 2020-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 7,916 2 0.03 4,937 27.77 0.0640
2020-05-11 2020-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 7,914 514 6.95 3,864 39.04 0.0442
2020-02-07 2019-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 7,400 50 0.68 2,779 35.69 0.0257
2019-11-06 2019-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 7,350 -2,700 -26.87 2,048 -34.67 0.0199
2019-08-07 2019-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 10,050 3,350 50.00 3,135 15.26 0.0318
2019-05-13 2019-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 6,700 2,000 42.55 2,720 54.99 0.0307
2019-02-12 2018-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 4,700 0 0.00 1,755 -7.58 0.0222
2018-11-13 2018-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 4,700 -12,100 -72.02 1,899 -67.24 0.0217
2018-08-14 2018-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 16,800 16,800 5,796 0.0675
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.