Rhythm Pharmaceuticals, Inc.
US ˙ NasdaqGM ˙ US76243J1051

SecurityRYTM / Rhythm Pharmaceuticals, Inc.
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Simplex Trading, Llc ownership in RYTM / Rhythm Pharmaceuticals, Inc.

On May 12, 2025 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 0 shares of Rhythm Pharmaceuticals, Inc. (US:RYTM) valued at $0 USD as of March 31, 2025. The entity filed a previous 13F-HR on February 11, 2025 disclosing 2,475 shares of Rhythm Pharmaceuticals, Inc.. The current value of the position is $0 USD.

Simplex Trading, 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 3,500 of underlying shares valued at $304,395 USD and put options representing 200 of underlying shares valued at $17,394 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.

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)
2025-05-12 2025-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -2,475 -100.00 0 0.0000
2025-02-11 2024-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 2,475 2,475 0 0.0001
2023-04-27 2023-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -5,581 -100.00 0 0.0000
2023-02-02 2022-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 5,581 5,581 0 0.0002
2022-11-04 2022-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -25,890 -100.00 0 -100.00
2022-08-03 2022-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 25,890 21,991 564.02 107 143.18 0.0001
2022-05-02 2022-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 3,899 551 16.46 44 33.33 0.0000
2022-02-23 2021-12-31 13F/A-1 RHYTHM PHARMACEUTICALS COM 76243J105 3,348 -1,056 -23.98 33 -63.74 0.0000
2022-02-04 2021-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 4,404 0 91 0.0000
2021-10-28 2021-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 4,404 -800 -15.37 91 -9.90 0.0001
2021-08-12 2021-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 5,204 488 10.35 101 1.00 0.0001
2021-04-26 2021-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 4,716 -5,484 -53.76 100 -67.00 0.0002
2021-02-02 2020-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 10,200 5,415 113.17 303 194.17 0.0004
2020-10-14 2020-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 4,785 4,785 -53.09 103 -66.01 0.0001
2020-07-13 2020-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -1,209 -100.00 0 -100.00
2020-04-29 2020-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 1,209 1,209 18 0.0000
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
(%)
2026-05-14 2026-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 3,500 600.00 304 473.58 n/a n/a n/a
2026-02-11 2025-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 500 66.67 54 n/a n/a n/a
2025-11-12 2025-09-30 13F RHYTHM PHARMACEUTICALS CALL Call 300 -96.20 0 n/a n/a n/a
2025-08-05 2025-06-30 13F RHYTHM PHARMACEUTICALS CALL Call 7,900 3.95 0 n/a n/a n/a
2025-05-12 2025-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 7,600 137.50 0 n/a n/a n/a
2025-02-11 2024-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 3,200 -81.82 0 n/a n/a n/a
2024-11-08 2024-09-30 13F RHYTHM PHARMACEUTICALS CALL Call 17,600 -45.51 1 -100.00 n/a n/a n/a
2024-07-25 2024-06-30 13F RHYTHM PHARMACEUTICALS CALL Call 32,300 173.73 1 n/a n/a n/a
2024-04-25 2024-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 11,800 -21.33 1 n/a n/a n/a
2024-02-02 2023-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 15,000 72.41 1 n/a n/a n/a
2023-11-01 2023-09-30 13F RHYTHM PHARMACEUTICALS CALL Call 8,700 -76.03 0 n/a n/a n/a
2023-08-04 2023-06-30 13F RHYTHM PHARMACEUTICALS CALL Call 36,300 175.00 1 n/a n/a n/a
2023-04-27 2023-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 13,200 500.00 0 n/a n/a n/a
2023-02-02 2022-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 2,200 -96.91 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F RHYTHM PHARMACEUTICALS CALL Call 71,200 4,646.67 1,744 28,966.67 n/a n/a n/a
2022-08-03 2022-06-30 13F RHYTHM PHARMACEUTICALS CALL Call 1,500 -55.88 6 -84.62 n/a n/a n/a
2022-05-02 2022-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 3,400 -10.53 39 5.41 n/a n/a n/a
2022-02-23 2021-12-31 13F/A RHYTHM PHARMACEUTICALS CALL Call 3,800 216.67 37 54.17 n/a n/a n/a
2022-02-04 2021-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 1,200 24 n/a n/a n/a
2021-10-28 2021-09-30 13F RHYTHM PHARMACEUTICALS CALL Call 1,200 0.00 24 4.35 n/a n/a n/a
2021-08-12 2021-06-30 13F RHYTHM PHARMACEUTICALS CALL Call 1,200 8,471.43 23 -20.69 n/a n/a n/a
2021-04-26 2021-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 14 -74.07 29 -81.87 n/a n/a n/a
2021-02-02 2020-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 54 45.95 160 100.00 n/a n/a n/a
2020-10-14 2020-09-30 13F RHYTHM PHARMACEUTICALS CALL Call 37 -31.48 80 -50.00 n/a n/a n/a
2020-07-13 2020-06-30 13F RHYTHM PHARMACEUTICALS CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-04-29 2020-03-31 13F RHYTHM PHARMACEUTICALS CALL Call 1 0.00 1 n/a n/a n/a
2020-02-05 2019-12-31 13F RHYTHM PHARMACEUTICALS CALL Call 1 0 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
(%)
2026-05-14 2026-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 200 -95.92 17 -96.76 n/a n/a n/a
2026-02-11 2025-12-31 13F RHYTHM PHARMACEUTICALS PUT Put 4,900 1,533.33 524 n/a n/a n/a
2025-11-12 2025-09-30 13F RHYTHM PHARMACEUTICALS PUT Put 300 -95.08 0 n/a n/a n/a
2025-08-05 2025-06-30 13F RHYTHM PHARMACEUTICALS PUT Put 6,100 454.55 0 n/a n/a n/a
2025-05-12 2025-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 1,100 -77.55 0 n/a n/a n/a
2025-02-11 2024-12-31 13F RHYTHM PHARMACEUTICALS PUT Put 4,900 -18.33 0 n/a n/a n/a
2024-11-08 2024-09-30 13F RHYTHM PHARMACEUTICALS PUT Put 6,000 172.73 0 n/a n/a n/a
2024-07-25 2024-06-30 13F RHYTHM PHARMACEUTICALS PUT Put 2,200 -38.89 0 n/a n/a n/a
2024-04-25 2024-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 3,600 -40.98 0 n/a n/a n/a
2024-02-02 2023-12-31 13F RHYTHM PHARMACEUTICALS PUT Put 6,100 90.62 0 n/a n/a n/a
2023-11-01 2023-09-30 13F RHYTHM PHARMACEUTICALS PUT Put 3,200 18.52 0 n/a n/a n/a
2023-08-04 2023-06-30 13F RHYTHM PHARMACEUTICALS PUT Put 2,700 -65.38 0 n/a n/a n/a
2023-04-27 2023-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 7,800 50.00 0 n/a n/a n/a
2023-02-02 2022-12-31 13F RHYTHM PHARMACEUTICALS PUT Put 5,200 -78.95 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F RHYTHM PHARMACEUTICALS PUT Put 24,700 -7.49 605 450.00 n/a n/a n/a
2022-08-03 2022-06-30 13F RHYTHM PHARMACEUTICALS PUT Put 26,700 444.90 110 96.43 n/a n/a n/a
2022-05-02 2022-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 4,900 -15.52 56 -1.75 n/a n/a n/a
2022-02-23 2021-12-31 13F/A RHYTHM PHARMACEUTICALS PUT Put 5,800 -46.79 57 -74.67 n/a n/a n/a
2022-02-04 2021-12-31 13F RHYTHM PHARMACEUTICALS PUT Put 10,900 225 n/a n/a n/a
2021-10-28 2021-09-30 13F RHYTHM PHARMACEUTICALS PUT Put 10,900 0.00 225 5.63 n/a n/a n/a
2021-08-12 2021-06-30 13F RHYTHM PHARMACEUTICALS PUT Put 10,900 10,586.27 213 -1.39 n/a n/a n/a
2021-04-26 2021-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 102 -62.22 216 -73.07 n/a n/a n/a
2021-02-02 2020-12-31 13F RHYTHM PHARMACEUTICALS PUT Put 270 8,900.00 802 13,266.67 n/a n/a n/a
2020-10-14 2020-09-30 13F RHYTHM PHARMACEUTICALS PUT Put 3 -98.89 6 -99.25 n/a n/a n/a
2020-07-13 2020-06-30 13F RHYTHM PHARMACEUTICALS PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-04-29 2020-03-31 13F RHYTHM PHARMACEUTICALS PUT Put 13 19 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.