Regeneron Pharmaceuticals, Inc.
MX ˙ BMV ˙ US75886F1075
SecurityMX:REGN / Regeneron Pharmaceuticals, Inc.
InstitutionCalamos Advisors LLC
Latest Disclosed Ownership11,793 shares
Latest Disclosed Value $ 9,111,744
Calamos Advisors LLC ownership in REGN / Regeneron Pharmaceuticals, Inc.

On May 4, 2026 - Calamos Advisors LLC filed a 13F-HR form disclosing ownership of 11,793 shares of Regeneron Pharmaceuticals, Inc. (MX:REGN) valued at $9,111,744 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 29, 2026 disclosing 11,793 shares of Regeneron Pharmaceuticals, Inc.. This represents a change in shares of 0.00% during the quarter.

Calamos Advisors LLC has a history of taking positions in derivatives of the underlying security (REGN) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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)
2026-05-04 2026-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 11,793 0 0.00 9,112 0.10 0.0321
2026-01-29 2025-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 11,793 -479 -3.90 9,103 31.91 0.0342
2025-10-20 2025-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 12,272 0 0.00 6,900 7.11 0.0255
2025-08-08 2025-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 12,272 0 0.00 6,443 -17.23 0.0254
2025-04-29 2025-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 12,272 -10,386 -45.84 7,783 -51.78 0.0339
2025-01-24 2024-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 22,658 10,523 86.72 16,140 26.52 0.0675
2024-11-07 2024-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 12,135 -298 -2.40 12,757 -2.38 0.0552
2024-07-25 2024-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 12,433 -454 -3.52 13,067 5.35 0.0580
2024-05-08 2024-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 12,887 -324 -2.45 12,404 6.89 0.0588
2024-01-31 2023-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 13,211 -173 -1.29 11,603 5.35 0.0563
2023-10-26 2023-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 13,384 0 0.00 11,014 14.54 0.0572
2023-07-28 2023-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 13,384 0 0.00 9,617 -12.56 0.0476
2023-05-04 2023-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 13,384 -1,687 -11.19 10,997 1.14 0.0537
2023-01-26 2022-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 15,071 -2,661 -15.01 10,874 -10.99 0.0510
2022-10-24 2022-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 17,732 -18 -0.10 12,215 16.41 0.0559
2022-08-01 2022-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 17,750 493 2.86 10,493 -12.94 0.0453
2022-05-03 2022-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 17,257 2,315 15.49 12,053 27.73 0.0452
2022-02-01 2021-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 14,942 578 4.02 9,436 8.55 0.0353
2021-10-26 2021-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 14,364 1,268 9.68 8,693 18.84 0.0380
2021-07-22 2021-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 13,096 2,979 29.45 7,315 52.81 0.0334
2021-04-12 2021-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 10,117 313 3.19 4,787 1.08 0.0261
2021-01-27 2020-12-31 13F REGENERON PHARMACEUTICALS COM 75886F107 9,804 -425 -4.15 4,736 -17.29 0.0275
2020-10-26 2020-09-30 13F REGENERON PHARMACEUTICALS COM 75886F107 10,229 -911 -8.18 5,726 -17.58 0.0369
2020-07-27 2020-06-30 13F REGENERON PHARMACEUTICALS COM 75886F107 11,140 -712 -6.01 6,947 20.04 0.0491
2020-04-28 2020-03-31 13F REGENERON PHARMACEUTICALS COM 75886F107 11,852 -979 -7.63 5,787 20.11 0.0454
2020-01-15 2019-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 12,831 -211 -1.62 4,818 33.17 0.0238
2019-10-21 2019-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 13,042 1,131 9.50 3,618 -2.95 0.0197
2019-08-07 2019-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 11,911 248 2.13 3,728 -22.15 0.0207
2019-04-12 2019-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 11,663 459 4.10 4,789 14.43 0.0299
2019-01-24 2018-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 11,204 1,678 17.61 4,185 8.73 0.0276
2018-10-22 2018-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 9,526 -5,122 -34.97 3,849 -23.83 0.0212
2018-07-17 2018-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 14,648 -2,535 -14.75 5,053 -14.62 0.0309
2018-04-13 2018-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 17,183 -103,083 -85.71 5,918 -86.91 0.0385
2018-02-13 2017-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 120,266 51,044 73.74 45,215 46.09 0.2304
2017-10-25 2017-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 69,222 57,538 492.45 30,951 439.40 0.2394
2017-08-09 2017-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 11,684 3,858 49.30 5,738 89.19 0.0424
2017-04-20 2017-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 7,826 3,811 94.92 3,033 105.77 0.0239
2017-02-06 2016-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 4,015 -52 -1.28 1,474 -9.85 0.0117
2016-11-14 2016-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 4,067 4 0.10 1,635 15.22 0.0117
2016-07-26 2016-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 4,063 1 0.02 1,419 -3.07 0.0100
2016-04-25 2016-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 4,062 253 6.64 1,464 -29.21 0.0097
2016-02-05 2015-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 3,809 0 0.00 2,068 16.70 0.0131
2015-11-10 2015-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 3,809 1 0.03 1,772 -8.80 0.0122
2015-08-14 2015-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 3,808 -23,115 -85.86 1,943 -84.01 0.0120
2015-05-13 2015-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 26,923 -167,202 -86.13 12,155 -84.74 0.0762
2015-02-13 2014-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 194,125 -109,637 -36.09 79,640 -27.28 0.5268
2014-11-14 2014-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 303,762 -20,395 -6.29 109,512 19.60 0.7309
2014-08-14 2014-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 324,157 -50,040 -13.37 91,565 -18.51 0.5803
2014-05-16 2014-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 374,197 40,069 11.99 112,364 22.18 0.7182
2014-02-14 2013-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 334,128 -93 -0.03 91,965 -12.05 0.5847
2013-11-14 2013-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 334,221 11,695 3.63 104,568 44.17 0.6559
2013-08-12 2013-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK 75886F107 322,526 322,526 72,530 0.4740
Disclosed Call 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
(%)
2015-05-13 2015-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-02-13 2014-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 215 -78.06 3,450 -68.60 n/a n/a n/a
2014-11-14 2014-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 980 -2.00 10,987 115.47 n/a n/a n/a
2014-08-14 2014-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 1,000 -49.70 5,099 -65.78 n/a n/a n/a
2014-05-16 2014-03-31 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 1,988 7.00 14,900 27.59 n/a n/a n/a
2014-02-14 2013-12-31 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 1,858 -4.86 11,678 -39.63 n/a n/a n/a
2013-11-14 2013-09-30 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 1,953 354.19 19,345 505.10 n/a n/a n/a
2013-08-12 2013-06-30 13F REGENERON PHARMACEUTICALS COMMON STOCK Call 430 3,197 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.