Rhythm Pharmaceuticals, Inc.
MX ˙ BMV ˙ US76243J1051
SecurityMX:RYTM / Rhythm Pharmaceuticals, Inc.
InstitutionJane Street Group, Llc
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Jane Street Group, Llc ownership in RYTM / Rhythm Pharmaceuticals, Inc.

On May 12, 2026 - Jane Street Group, Llc filed a 13F-HR form disclosing ownership of 0 shares of Rhythm Pharmaceuticals, Inc. (MX:RYTM) valued at $0 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 1,960 shares of Rhythm Pharmaceuticals, Inc.. This represents a change in shares of -100.00% during the quarter.

Jane Street Group, Llc has a history of taking positions in derivatives of the underlying security (RYTM) in the form of stock options. The firm currently holds call options representing 46,500 of underlying shares valued at $4,044,105 USD and put options representing 3,900 of underlying shares valued at $339,183 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:RYTM / Rhythm 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)
2026-05-12 2026-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -1,960 -100.00 0 -100.00
2026-02-12 2025-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 1,960 -1,008 -33.96 210 -30.10 0.0000
2025-11-14 2025-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 2,968 2,968 300 0.0000
2025-08-14 2025-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -91,118 -100.00 0 -100.00
2025-05-19 2025-03-31 13F/A-1 RHYTHM PHARMACEUTICALS COM 76243J105 91,118 32,703 55.98 4,827 47.58 0.0012
2025-05-14 2025-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 91,118 32,703 4,827 0.0010
2025-02-14 2024-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 58,415 -50,771 -46.50 3,270 -42.83 0.0007
2024-11-15 2024-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 109,186 -37,314 -25.47 5,720 -4.90 0.0013
2024-08-15 2024-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 146,500 120,182 456.65 6,015 427.63 0.0014
2024-05-16 2024-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 26,318 -158,041 -85.72 1,140 -86.55 0.0002
2024-02-15 2023-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 184,359 40,357 28.03 8,475 156.71 0.0022
2023-11-15 2023-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 144,002 67,978 89.42 3,301 163.45 0.0011
2023-08-14 2023-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 76,024 -273,615 -78.26 1,254 -79.91 0.0004
2023-05-16 2023-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 349,639 150,136 75.26 6,238 7.37 0.0026
2023-02-15 2022-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 199,503 199,503 5,810 0.0027
2022-08-16 2022-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -18,923 -100.00 0 -100.00
2022-05-17 2022-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 18,923 18,923 218 0.0001
2021-08-16 2021-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -11,770 -100.00 0 -100.00
2021-05-18 2021-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 11,770 2,932 33.17 251 -4.56 0.0001
2021-02-17 2020-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 8,838 8,838 263 0.0001
2020-11-17 2020-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -9,505 -100.00 0 -100.00
2020-08-17 2020-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 9,505 -2,516 -20.93 212 15.85 0.0002
2020-05-15 2020-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 12,021 12,021 183 0.0002
2018-11-14 2018-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -12,056 -100.00 0 -100.00
2018-08-15 2018-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 12,056 12,056 377 0.0009
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
(%)
2026-05-12 2026-03-31 13F RHYTHM PHARMACEUTICALS COM Call 46,500 -66.23 4,044 -72.56 n/a n/a n/a
2026-02-12 2025-12-31 13F RHYTHM PHARMACEUTICALS COM Call 137,700 88.63 14,739 99.93 n/a n/a n/a
2025-11-14 2025-09-30 13F RHYTHM PHARMACEUTICALS COM Call 73,000 4.89 7,372 67.62 n/a n/a n/a
2025-08-14 2025-06-30 13F RHYTHM PHARMACEUTICALS COM Call 69,600 -59.08 4,398 -51.19 n/a n/a n/a
2025-05-19 2025-03-31 13F/A RHYTHM PHARMACEUTICALS COM Call 170,100 73.57 9,010 64.24 n/a n/a n/a
2025-05-14 2025-03-31 13F RHYTHM PHARMACEUTICALS COM Call 170,100 9,010 n/a n/a n/a
2025-02-14 2024-12-31 13F RHYTHM PHARMACEUTICALS COM Call 98,000 -47.40 5,486 -43.79 n/a n/a n/a
2024-11-15 2024-09-30 13F RHYTHM PHARMACEUTICALS COM Call 186,300 125.27 9,760 187.48 n/a n/a n/a
2024-08-15 2024-06-30 13F RHYTHM PHARMACEUTICALS COM Call 82,700 -10.11 3,396 -14.83 n/a n/a n/a
2024-05-16 2024-03-31 13F RHYTHM PHARMACEUTICALS COM Call 92,000 -58.37 3,986 -60.76 n/a n/a n/a
2024-02-15 2023-12-31 13F RHYTHM PHARMACEUTICALS COM Call 221,000 37.27 10,159 175.31 n/a n/a n/a
2023-11-15 2023-09-30 13F RHYTHM PHARMACEUTICALS COM Call 161,000 507.55 3,691 746.33 n/a n/a n/a
2023-08-14 2023-06-30 13F RHYTHM PHARMACEUTICALS COM Call 26,500 9.50 437 1.16 n/a n/a n/a
2023-05-16 2023-03-31 13F RHYTHM PHARMACEUTICALS COM Call 24,200 -71.19 432 -82.38 n/a n/a n/a
2023-02-15 2022-12-31 13F RHYTHM PHARMACEUTICALS COM Call 84,000 -71.38 2,446 -65.99 n/a n/a n/a
2022-11-15 2022-09-30 13F RHYTHM PHARMACEUTICALS COM Call 293,500 7,191 n/a n/a n/a
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
(%)
2026-05-12 2026-03-31 13F RHYTHM PHARMACEUTICALS COM Put 3,900 339 n/a n/a n/a
2026-02-12 2025-12-31 13F RHYTHM PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-14 2025-09-30 13F RHYTHM PHARMACEUTICALS COM Put 14,700 -72.11 1,485 -55.44 n/a n/a n/a
2025-08-14 2025-06-30 13F RHYTHM PHARMACEUTICALS COM Put 52,700 3,330 n/a n/a n/a
2025-02-14 2024-12-31 13F RHYTHM PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-11-15 2024-09-30 13F RHYTHM PHARMACEUTICALS COM Put 18,700 -35.96 980 -18.28 n/a n/a n/a
2024-08-15 2024-06-30 13F RHYTHM PHARMACEUTICALS COM Put 29,200 -49.13 1,199 -51.83 n/a n/a n/a
2024-05-16 2024-03-31 13F RHYTHM PHARMACEUTICALS COM Put 57,400 310.00 2,487 286.78 n/a n/a n/a
2024-02-15 2023-12-31 13F RHYTHM PHARMACEUTICALS COM Put 14,000 644 n/a n/a n/a
2023-05-15 2023-03-31 13F RHYTHM PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-02-15 2022-12-31 13F RHYTHM PHARMACEUTICALS COM Put 102,800 -17.76 2,994 -2.29 n/a n/a n/a
2022-11-15 2022-09-30 13F RHYTHM PHARMACEUTICALS COM Put 125,000 3,063 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.