Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionGrandfield & Dodd, Llc
Latest Disclosed Ownership36,415 shares
Latest Disclosed Value $ 28,135,740
Grandfield & Dodd, Llc reports 0.42% decrease in ownership of REGN / Regeneron Pharmaceuticals, Inc.

On May 7, 2026 - Grandfield & Dodd, Llc filed a 13F-HR form disclosing ownership of 36,415 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $28,135,740 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 36,568 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of -0.42% 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 36,415 -153 -0.42 28,136 -0.32 1.5886
2026-02-10 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 36,568 117 0.32 28,226 37.72 1.5986
2025-10-30 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 36,451 1,246 3.54 20,495 10.89 1.1627
2025-08-08 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 35,205 1,998 6.02 18,483 -12.24 1.0824
2025-05-02 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 33,207 611 1.87 21,061 -9.30 1.3058
2025-02-06 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 32,596 268 0.83 23,219 -31.68 1.4316
2024-11-08 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 32,328 -8 -0.02 33,984 -0.01 2.0139
2024-08-09 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 32,336 59 0.18 33,986 9.40 2.1517
2024-05-06 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 32,277 75 0.23 31,066 9.84 1.9604
2024-01-31 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 32,202 -40 -0.12 28,283 6.59 1.9543
2023-10-26 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 32,242 763 2.42 26,534 17.31 1.9494
2023-08-08 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 31,479 554 1.79 22,619 -10.99 1.5812
2023-04-28 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 30,925 449 1.47 25,410 15.56 1.7759
2023-01-20 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 30,476 204 0.67 21,988 5.46 1.6088
2022-11-04 2022-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 30,272 998 3.41 20,850 20.52 1.7023
2022-08-01 2022-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 29,274 500 1.74 17,300 -13.93 1.3626
2022-04-19 2022-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 28,774 977 3.51 20,100 14.53 1.3640
2022-02-08 2021-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 27,797 1,766 6.78 17,550 11.43 1.1290
2021-10-28 2021-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 26,031 4,395 20.31 15,750 30.38 1.0994
2021-07-28 2021-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 21,636 3,074 16.56 12,080 37.59 0.8360
2021-04-22 2021-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 18,562 807 4.55 8,780 2.33 0.6564
2021-01-29 2020-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 17,755 1,085 6.51 8,580 -8.04 0.6732
2020-11-03 2020-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 16,670 9 0.05 9,330 -10.20 0.8403
2020-07-24 2020-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 16,661 -423 -2.48 10,390 24.55 1.0053
2020-05-14 2020-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 17,084 1,119 7.01 8,342 39.15 0.9836
2020-02-07 2019-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 15,965 2,348 17.24 5,995 58.72 0.5461
2019-10-30 2019-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 13,617 2,019 17.41 3,777 4.05 0.3716
2019-07-29 2019-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 11,598 2,620 29.18 3,630 -1.55 0.3588
2019-04-26 2019-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 8,978 283 3.25 3,687 13.52 0.3840
2019-02-12 2018-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 8,695 1,522 21.22 3,248 12.08 0.3844
2018-11-02 2018-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 7,173 1,327 22.70 2,898 43.68 0.2986
2018-07-27 2018-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 5,846 3,401 139.10 2,017 139.55 0.2216
2018-05-04 2018-03-31 13F/A-1 REGENERON PHARMACEUTICALS COM 75886F107 2,445 711 41.00 842 29.14 0.0939
2018-05-04 2018-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 2,445 711 842
2018-02-05 2017-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 1,734 87 5.28 652 -11.41 0.0696
2017-11-03 2017-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,647 115 7.51 736 -2.13 0.0826
2017-07-27 2017-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,532 35 2.34 752 29.66 0.0889
2017-04-28 2017-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 1,497 17 1.15 580 6.81 0.0716
2017-02-02 2016-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 1,480 180 13.85 543 3.82 0.0704
2016-10-24 2016-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,300 125 10.64 523 27.56 0.0687
2016-07-28 2016-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,175 48 4.26 410 0.99 0.0574
2016-05-06 2016-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 1,127 347 44.49 406 -4.02 0.0588
2016-02-03 2015-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 780 107 15.90 423 35.14 0.0643
2015-11-02 2015-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 673 -26 -3.72 313 -12.32 0.0525
2015-08-03 2015-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 699 -43 -5.80 357 6.57 0.0546
2015-05-15 2015-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 742 0 0.00 335 10.20 0.0512
2015-02-05 2014-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 742 0 0.00 304 13.43 0.0470
2014-11-10 2014-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 742 20 2.77 268 31.37 0.0421
2014-08-14 2014-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 722 45 6.65 204 0.49 0.0308
2014-05-06 2014-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 677 677 203 0.0319
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.