Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionAcadian Asset Management Llc
Latest Disclosed Ownership151,191 shares
Latest Disclosed Value $ 116,782
Acadian Asset Management Llc reports 66.09% decrease in ownership of REGN / Regeneron Pharmaceuticals, Inc.

On May 13, 2026 - Acadian Asset Management Llc filed a 13F-HR form disclosing ownership of 151,191 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $116,782 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 445,795 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of -66.09% 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)
2026-05-13 2026-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 151,191 -294,604 -66.09 117 -66.28 0.1657
2026-02-10 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 445,795 -138,710 -23.73 344 4.88 0.5649
2025-11-13 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 584,505 118,765 25.50 329 34.43 0.5735
2025-08-07 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 465,740 326,583 234.69 244 177.27 0.5047
2025-05-21 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 139,157 56,816 69.00 88 51.72 0.2494
2025-02-11 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 82,341 15,052 22.37 59 -17.14 0.1701
2024-11-12 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 67,289 -5,541 -7.61 71 -7.89 0.2197
2024-08-06 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 72,830 10,689 17.20 77 28.81 0.2357
2024-05-10 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 62,141 16,856 37.22 60 51.28 0.2083
2024-02-13 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 45,285 -26,007 -36.48 40 -32.76 0.1541
2023-11-13 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 71,292 -10,784 -13.14 59 0.00 0.2458
2023-08-07 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 82,076 -20,953 -20.34 59 -30.95 0.2423
2023-05-11 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 103,029 -97,354 -48.58 85 -41.67 0.3710
2023-02-14 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 200,383 -60,612 -23.22 145 -99.92 0.7121
2022-11-14 2022-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 260,995 -98,420 -27.38 179,756 -15.40 0.9833
2022-08-09 2022-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 359,415 -69,783 -16.26 212,465 -29.11 1.0865
2022-05-12 2022-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 429,198 -22,995 -5.09 299,719 4.97 1.2355
2022-02-10 2021-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 452,193 -77,272 -14.59 285,527 -10.88 1.0667
2021-11-12 2021-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 529,465 87,815 19.88 320,383 29.88 1.2216
2021-08-11 2021-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 441,650 16,276 3.83 246,684 22.57 0.9285
2021-05-11 2021-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 425,374 331,154 351.47 201,262 342.17 0.7820
2021-02-11 2020-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 94,220 -1,279 -1.34 45,517 -14.85 0.1760
2020-11-09 2020-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 95,499 15,280 19.05 53,458 6.85 0.2240
2020-08-12 2020-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 80,219 76,654 2,150.18 50,031 2,773.69 0.2154
2020-05-11 2020-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 3,565 1,638 85.00 1,741 140.47 0.0100
2020-02-06 2019-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 1,927 1,004 108.78 724 182.81 0.0033
2019-11-07 2019-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 923 -1,065 -53.57 256 -58.84 0.0011
2019-08-08 2019-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,988 -2,836 -58.79 622 -68.59 0.0030
2019-05-09 2019-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 4,824 -18,790 -79.57 1,980 -77.56 0.0085
2019-02-07 2018-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 23,614 2,479 11.73 8,822 3.29 0.0437
2018-10-30 2018-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 21,135 19,649 1,322.27 8,541 1,564.91 0.0353
2018-07-24 2018-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,486 1,486 513 0.0022
2018-04-12 2018-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -202 -100.00 0 -100.00
2018-01-18 2017-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 202 -262 -56.47 76 -63.46 0.0003
2017-10-13 2017-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 464 -1,032 -68.98 208 -71.70 0.0009
2017-07-25 2017-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,496 1,429 2,132.84 735 2,726.92 0.0033
2017-04-25 2017-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 67 -151 -69.27 26 -67.90 0.0001
2017-01-19 2016-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 218 -516 -70.30 81 -72.54 0.0004
2016-10-20 2016-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 734 -1,149 -61.02 295 -55.10 0.0015
2016-07-19 2016-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,883 1,164 161.89 657 153.67 0.0034
2016-04-14 2016-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 719 0 0.00 259 -33.59 0.0013
2016-01-14 2015-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 719 0 0.00 390 16.77 0.0020
2015-10-15 2015-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 719 0 0.00 334 -8.99 0.0018
2015-08-11 2015-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 719 -191 -20.99 367 -10.71 0.0018
2015-04-20 2015-03-31 13F/A-1 REGENERON PHARMACEUTICALS COM 75886F107 910 0 0.00 411 10.19 0.0019
2015-01-23 2014-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 910 910 373 0.0017
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.