Rhythm Pharmaceuticals, Inc.
MX ˙ BMV ˙ US76243J1051
SecurityMX:RYTM / Rhythm Pharmaceuticals, Inc.
InstitutionWoodline Partners LP
Latest Disclosed Ownership758,891 shares
Latest Disclosed Value $ 66,000,750
Woodline Partners LP reports 10.18% increase in ownership of RYTM / Rhythm Pharmaceuticals, Inc.

On May 15, 2026 - Woodline Partners LP filed a 13F-HR/A form disclosing ownership of 758,891 shares of Rhythm Pharmaceuticals, Inc. (MX:RYTM) valued at $66,000,750 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 688,779 shares of Rhythm Pharmaceuticals, Inc.. This represents a change in shares of 10.18% 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)
2026-05-15 2026-03-31 13F/A-1 RHYTHM PHARMACEUTICALS COM 76243J105 758,891 70,112 10.18 66,001 -10.48 0.2496
2026-05-15 2026-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 758,891 70,112 66,001 0.2495
2026-02-17 2025-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 688,779 108,596 18.72 73,727 25.83 0.2857
2025-11-14 2025-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 580,183 65,802 12.79 58,593 80.27 0.2758
2025-08-14 2025-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 514,381 514,381 32,504 0.1717
2025-02-14 2024-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -143,823 -100.00 0 -100.00
2024-11-14 2024-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 143,823 99,576 225.05 7,535 314.87 0.0635
2024-08-14 2024-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 44,247 -127,960 -74.31 1,817 -75.66 0.0173
2024-05-15 2024-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 172,207 97,357 130.07 7,462 116.89 0.0687
2024-02-14 2023-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 74,850 74,850 3,441 0.0374
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.