Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionMarex Group plc
Latest Disclosed Ownership1,739 shares
Latest Disclosed Value $ 1,343,621
Marex Group plc ownership in REGN / Regeneron Pharmaceuticals, Inc.

On May 13, 2026 - Marex Group plc filed a 13F-HR form disclosing ownership of 1,739 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $1,343,621 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 31,189 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of -94.42% during the quarter.

Marex Group plc 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.

MX: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)
2026-05-13 2026-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 1,739 -29,450 -94.42 1,344 -94.42 0.0085
2026-02-12 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 31,189 -19,769 -38.79 24,074 -15.98 0.1515
2025-11-14 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 50,958 -475 -0.92 28,652 6.11 0.2025
2025-08-19 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 51,433 -19,435 -27.42 27,002 -39.92 0.2342
2026-04-02 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 70,868 603 0.86 44,947 -10.20 0.8613
2026-04-02 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 70,265 35,062 99.60 50,052 35.25 0.8526
2026-04-07 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 35,203 35,203 37,007 0.8441
2026-04-02 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 0 0 0 0.0000
2026-04-02 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -25,216 -100.00 0 -100.00
2026-04-02 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 25,216 25,216 22,147 0.8705
2026-04-02 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 0 -330 -100.00 0 -100.00
2026-04-02 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 330 330 238 0.0338
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
(%)
2026-05-13 2026-03-31 13F REGENERON PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-12 2025-12-31 13F REGENERON PHARMACEUTICALS COM Put 30,000 -40.00 23,156 -17.63 n/a n/a n/a
2025-11-14 2025-09-30 13F REGENERON PHARMACEUTICALS COM Put 50,000 0.00 28,114 7.10 n/a n/a n/a
2025-08-19 2025-06-30 13F REGENERON PHARMACEUTICALS COM Put 50,000 26,250 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.