Regeneron Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US75886F1075

SecurityREGN / Regeneron Pharmaceuticals, Inc.
InstitutionBoothbay Fund Management, Llc
Latest Disclosed Ownership2,972 shares
Latest Disclosed Value $ 2,296,286
Boothbay Fund Management, Llc ownership in REGN / Regeneron Pharmaceuticals, Inc.

On May 15, 2026 - Boothbay Fund Management, Llc filed a 13F-HR form disclosing ownership of 2,972 shares of Regeneron Pharmaceuticals, Inc. (US:REGN) valued at $2,296,286 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 0 shares of Regeneron Pharmaceuticals, Inc.. The current value of the position is $1,888,557 USD.

Boothbay Fund Management, Llc has a history of taking positions in derivatives of the underlying security (REGN) in the form of stock options.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

REGN / Regeneron Pharmaceuticals, Inc. Historical Put/Call Ratio
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)
2026-05-15 2026-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 2,972 2,972 2,296 0.0298
2026-02-17 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -4,240 -100.00 0 -100.00
2025-11-14 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 4,240 1,541 57.10 2,384 68.36 0.0347
2025-08-14 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 2,699 2,699 1,417 0.0275
2025-05-15 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -12,375 -100.00 0 -100.00
2025-02-14 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 12,375 11,239 989.35 8,815 638.27 0.2174
2024-11-14 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 1,136 1,136 1,194 0.0272
2024-08-14 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -5,081 -100.00 0 -100.00
2024-05-15 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 5,081 5,081 4,890 0.0942
2023-11-14 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -10,590 -100.00 0 -100.00
2023-08-14 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 10,590 10,226 2,809.34 7,609 2,444.82 0.1669
2023-05-15 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 364 80 28.17 299 46.57 0.0061
2023-02-14 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 284 284 205 0.0047
2020-11-16 2020-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -4,000 -100.00 0 -100.00
2020-08-14 2020-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 4,000 -1,000 -20.00 2,495 2.21 0.1706
2020-05-15 2020-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 5,000 -2,000 -28.57 2,441 -7.12 0.2023
2020-02-14 2019-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 7,000 -2 -0.03 2,628 35.32 0.2286
2019-11-14 2019-09-30 13F Regeneron Pharmaceuticals COM 75886F107 7,002 887 14.51 1,942 1.46 0.1781
2019-08-14 2019-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 6,115 6,115 1,914 0.1741
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2020-08-14 2020-06-30 13F REGENERON PHARMACEUTICALS PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-05-15 2020-03-31 13F REGENERON PHARMACEUTICALS PUT Put 98 4,785 n/a n/a n/a
2018-11-14 2018-09-30 13F REGENERON PHARMACEUTICALS PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-08-14 2018-06-30 13F REGENERON PHARMACEUTICALS PUT Put 476 16,422 n/a n/a n/a
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.