Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionGreat Diamond Partners, LLC
Latest Disclosed Ownership484 shares
Latest Disclosed Value $ 373,958
Great Diamond Partners, LLC reports 2.02% decrease in ownership of REGN / Regeneron Pharmaceuticals, Inc.

On May 12, 2026 - Great Diamond Partners, LLC filed a 13F-HR form disclosing ownership of 484 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $373,958 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 494 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of -2.02% 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)
2026-05-12 2026-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 484 -10 -2.02 374 -2.10 0.0720
2026-02-06 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 494 -33 -6.26 381 28.72 0.0734
2025-10-20 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 527 -8 -1.50 296 5.71 0.0575
2025-08-13 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 535 108 25.29 281 3.70 0.0593
2025-05-13 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 427 98 29.79 271 15.38 0.0740
2025-01-23 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 329 -6 -1.79 234 -33.52 0.0606
2024-10-25 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 335 -254 -43.12 352 -43.13 0.0895
2024-07-29 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 589 -10 -1.67 619 7.47 0.1455
2024-05-08 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 599 -8 -1.32 577 8.07 0.1324
2024-02-07 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 607 -17 -2.72 533 3.90 0.1314
2023-10-19 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 624 1 0.16 514 14.77 0.1390
2023-07-17 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 623 26 4.36 448 -8.78 0.1182
2023-05-04 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 597 4 0.67 491 14.75 0.1421
2023-02-01 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 593 -129 -17.87 428 -14.08 0.1317
2022-10-24 2022-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 722 1 0.14 497 16.67 0.1699
2022-07-26 2022-06-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 721 -196 -21.37 426 -33.44 0.1416
2022-05-05 2022-03-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 917 -53 -5.46 640 4.58 0.1781
2022-01-26 2021-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 970 1 0.10 612 4.44 0.1576
2021-10-21 2021-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 969 -2 -0.21 586 8.12 0.1606
2021-07-26 2021-06-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 971 0 0.00 542 18.08 0.1533
2021-05-04 2021-03-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 971 -46 -4.52 459 -6.52 0.1412
2021-01-26 2020-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 1,017 -67 -6.18 491 -18.98 0.1565
2020-10-19 2020-09-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 1,084 6 0.56 606 -9.82 0.2224
2020-08-04 2020-06-30 13F REGENERON PHARMACEUTICALS COM COM 75886F107 1,078 -54 -4.77 672 21.74 0.2782
2020-05-01 2020-03-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 1,132 -37 -3.17 552 26.03 0.2841
2020-02-07 2019-12-31 13F REGENERON PHARMACEUTICALS COM COM 75886F107 1,169 1,169 438 0.1665
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.