Rhythm Pharmaceuticals, Inc.
MX ˙ BMV ˙ US76243J1051
SecurityMX:RYTM / Rhythm Pharmaceuticals, Inc.
InstitutionBaker Bros. Advisors Lp
ManagerJulian and Felix Baker
Latest Disclosed Ownership5,604,483 shares
Ownership 8.90%
Baker Bros. Advisors Lp ownership in RYTM / Rhythm Pharmaceuticals, Inc.

2025-05-15 - Baker Bros. Advisors Lp has filed an SCHEDULE 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 5,604,483 shares of Rhythm Pharmaceuticals, Inc. (MX:RYTM). This represents 8.9 percent ownership of the company. In their previous filing dated 2024-02-14 , Baker Bros. Advisors Lp had reported owning 6,398,365 shares, indicating a decrease of -12.41 percent.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date		Effective
Date		Form Prev
Shares		 Latest
Shares		 ΔShares
(Percent)		 Ownership
(Percent)		 ΔOwnership
(Percent)
2025-05-15 2025-05-15 13G/A 6,398,365 5,604,483 -12.41 8.90 -17.59
2024-02-14 2024-02-14 13G/A 6,354,608 6,398,365 0.69 10.80 -4.42
2023-02-14 2023-02-14 13G/A 6,062,702 6,354,608 4.81 11.30 3.67
2022-10-07 2022-10-07 13G/A 3,863,239 6,062,702 56.93 10.90 41.56
2022-02-14 2022-02-14 13G/A 2,314,873 3,863,239 66.89 7.70 48.08
2021-02-16 2021-02-16 13G/A 2,708,200 2,314,873 -14.52 5.20 -34.18
2019-02-13 2019-02-13 13G/A 2,049,020 2,708,200 32.17 7.90 5.33
2018-02-13 2018-02-13 13G 2,049,020 7.50

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

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 Rhythm Pharmaceuticals COM 76243J105 5,604,483 0 0.00 487,422 -18.75 2.7988
2026-02-17 2025-12-31 13F Rhythm Pharmaceuticals COM 76243J105 5,604,483 0 0.00 599,904 5.99 3.5126
2025-11-14 2025-09-30 13F Rhythm Pharmaceuticals COM 76243J105 5,604,483 0 0.00 565,997 59.82 4.0899
2025-08-14 2025-06-30 13F Rhythm Pharmaceuticals COM 76243J105 5,604,483 0 0.00 354,147 19.29 3.4357
2025-05-15 2025-03-31 13F Rhythm Pharmaceuticals COM 76243J105 5,604,483 -479,766 -7.89 296,869 -12.84 3.2852
2025-02-14 2024-12-31 13F Rhythm Pharmaceuticals COM 76243J105 6,084,249 -314,117 -4.91 340,596 1.61 3.6383
2024-11-14 2024-09-30 13F Rhythm Pharmaceuticals COM 76243J105 6,398,366 1 0.00 335,210 27.59 3.4741
2024-08-14 2024-06-30 13F Rhythm Pharmaceuticals COM 76243J105 6,398,365 0 0.00 262,717 -5.24 3.3574
2024-05-15 2024-03-31 13F Rhythm Pharmaceuticals COM 76243J105 6,398,365 0 0.00 277,241 -5.74 3.4778
2024-02-14 2023-12-31 13F Rhythm Pharmaceuticals COM 76243J105 6,398,365 -303,984 -4.54 294,133 91.43 3.3468
2023-11-14 2023-09-30 13F Rhythm Pharmaceuticals COM 76243J105 6,702,349 204,082 3.14 153,651 43.39 0.8855
2023-08-14 2023-06-30 13F Rhythm Pharmaceuticals COM 76243J105 6,498,267 0 0.00 107,156 -7.57 0.6201
2023-05-15 2023-03-31 13F Rhythm Pharmaceuticals COM 76243J105 6,498,267 143,659 2.26 115,929 -37.35 0.6307
2023-02-14 2022-12-31 13F Rhythm Pharmaceuticals COM 76243J105 6,354,608 291,906 4.81 185,046 24.58 1.1113
2022-11-14 2022-09-30 13F Rhythm Pharmaceuticals COM 76243J105 6,062,702 1,937,640 46.97 148,536 767.67 0.9728
2022-08-15 2022-06-30 13F Rhythm Pharmaceuticals COM 76243J105 4,125,062 0 0.00 17,119 -63.98 0.0971
2022-05-16 2022-03-31 13F Rhythm Pharmaceuticals COM 76243J105 4,125,062 261,823 6.78 47,521 23.26 0.2731
2022-02-14 2021-12-31 13F Rhythm Pharmaceuticals COM 76243J105 3,863,239 0 0.00 38,555 -23.58 0.1876
2021-11-15 2021-09-30 13F Rhythm Pharmaceuticals COM 76243J105 3,863,239 0 0.00 50,454 -33.30 0.2216
2021-08-16 2021-06-30 13F Rhythm Pharmaceuticals COM 76243J105 3,863,239 383,366 11.02 75,642 2.20 0.3322
2021-05-17 2021-03-31 13F Rhythm Pharmaceuticals COM 76243J105 3,479,873 1,165,000 50.33 74,017 7.55 0.3209
2021-02-16 2020-12-31 13F Rhythm Pharmaceuticals COM 76243J105 2,314,873 -156,282 -6.32 68,821 28.52 0.2593
2020-11-16 2020-09-30 13F Rhythm Pharmaceuticals COM 76243J105 2,471,155 -228,900 -8.48 53,550 -11.06 0.2140
2020-08-14 2020-06-30 13F Rhythm Pharmaceuticals COM 76243J105 2,700,055 -8,145 -0.30 60,211 46.08 0.2656
2020-05-15 2020-03-31 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 41,219 -33.71 0.2539
2020-02-14 2019-12-31 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 62,180 6.35 0.3306
2019-11-14 2019-09-30 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 58,470 -1.86 0.3978
2019-08-14 2019-06-30 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 59,580 -19.74 0.4049
2019-05-15 2019-03-31 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 74,232 1.97 0.4752
2019-02-13 2018-12-31 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 72,796 -7.85 0.5961
2018-11-14 2018-09-30 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 0 0.00 78,998 -6.69 0.5204
2018-08-14 2018-06-30 13F Rhythm Pharmaceuticals COM 76243J105 2,708,200 659,180 32.17 84,658 107.62 0.6361
2018-05-15 2018-03-31 13F Rhythm Pharmaceuticals COM NEW 76243J105 2,049,020 0 0.00 40,775 -31.52 0.3456
2018-02-14 2017-12-31 13F Rhythm Pharmaceuticals COM 76243J105 2,049,020 2,049,020 59,545 0.5161
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.