Rhythm Pharmaceuticals, Inc.
MX ˙ BMV ˙ US76243J1051
SecurityMX:RYTM / Rhythm Pharmaceuticals, Inc.
InstitutionSG Americas Securities, LLC
Latest Disclosed Ownership18,760 shares
Latest Disclosed Value $ 1,632
SG Americas Securities, LLC reports 59.78% increase in ownership of RYTM / Rhythm Pharmaceuticals, Inc.

On April 16, 2026 - SG Americas Securities, LLC filed a 13F-HR form disclosing ownership of 18,760 shares of Rhythm Pharmaceuticals, Inc. (MX:RYTM) valued at $1,632 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 9, 2026 disclosing 11,741 shares of Rhythm Pharmaceuticals, Inc.. This represents a change in shares of 59.78% during the quarter.

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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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)
2026-04-16 2026-03-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 18,760 7,019 59.78 2 0.00 0.0018
2026-01-09 2025-12-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 11,741 -7,813 -39.96 1 0.00 0.0016
2025-10-23 2025-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 19,554 13,369 216.15 2 0.0067
2025-08-08 2025-06-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 6,185 -13,482 -68.55 0 -100.00 0.0016
2025-04-15 2025-03-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 19,667 19,667 1 0.0034
2025-01-17 2024-12-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 0 -7,519 -100.00 0 0.0000
2024-10-03 2024-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 7,519 -26,208 -77.71 0 -100.00 0.0014
2024-07-12 2024-06-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 33,727 26,214 348.92 1 0.0081
2024-05-06 2024-03-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 7,513 13 0.17 0 0.0016
2024-01-12 2023-12-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 7,500 -37,374 -83.29 0 -100.00 0.0032
2023-10-13 2023-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 44,874 44,874 1 0.0118
2022-10-31 2022-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 0 -80,064 -100.00 0 -100.00
2022-07-29 2022-06-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 80,064 -5,118 -6.01 332 -66.16 0.0035
2022-04-29 2022-03-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 85,182 -6,477 -7.07 981 7.21 0.0072
2022-02-07 2021-12-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 91,659 -17,644 -16.14 915 -35.88 0.0050
2021-11-01 2021-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 109,303 27,435 33.51 1,427 -10.98 0.0067
2021-08-12 2021-06-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 81,868 -4,916 -5.66 1,603 -13.16 0.0075
2021-05-13 2021-03-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 86,784 -23,904 -21.60 1,846 -43.91 0.0097
2021-02-04 2020-12-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 110,688 20,390 22.58 3,291 68.17 0.0176
2020-11-09 2020-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 90,298 90,298 1,957 0.0125
2020-07-20 2020-06-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 0 -11,382 -100.00 0 -100.00
2020-04-30 2020-03-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 11,382 -3,837 -25.21 173 -50.43 0.0016
2020-01-28 2019-12-31 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 15,219 -56,422 -78.76 349 -77.44 0.0032
2019-11-04 2019-09-30 13F RHYTHM PHARMACEUTICALS INC COM COM 76243J105 71,641 71,641 1,547 0.0127
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.