Rhythm Pharmaceuticals, Inc.
US ˙ NasdaqGM ˙ US76243J1051

SecurityRYTM / Rhythm Pharmaceuticals, Inc.
InstitutionNorthern Trust Corp
Latest Disclosed Ownership498,514 shares
Latest Disclosed Value $ 43,355,763
Northern Trust Corp reports 2.11% increase in ownership of RYTM / Rhythm Pharmaceuticals, Inc.

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 498,514 shares of Rhythm Pharmaceuticals, Inc. (US:RYTM) valued at $43,355,763 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 488,216 shares of Rhythm Pharmaceuticals, Inc.. This represents a change in shares of 2.11% during the quarter. The current value of the position is $43,674,812 USD.

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)
2026-05-14 2026-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 498,514 10,298 2.11 43,356 -17.04 0.0057
2026-02-17 2025-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 488,216 -22,690 -4.44 52,259 1.28 0.0067
2025-11-14 2025-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 510,906 660 0.13 51,596 60.03 0.0066
2025-08-13 2025-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 510,246 -25,960 -4.84 32,242 13.52 0.0044
2025-05-13 2025-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 536,206 -9,108 -1.67 28,403 -6.96 0.0042
2025-02-14 2024-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 545,314 46,848 9.40 30,527 16.90 0.0043
2024-11-13 2024-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 498,466 -982 -0.20 26,115 27.34 0.0043
2024-08-14 2024-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 499,448 -3,407 -0.68 20,507 -5.88 0.0035
2024-05-14 2024-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 502,855 1,761 0.35 21,789 -5.41 0.0038
2024-02-13 2023-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 501,094 -2,928 -0.58 23,035 99.37 0.0042
2023-11-13 2023-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 504,022 9,820 1.99 11,555 41.78 0.0022
2023-08-11 2023-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 494,202 352,065 247.69 8,149 221.46 0.0016
2023-05-15 2023-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 142,137 4,036 2.92 2,536 -36.96 0.0005
2023-02-13 2022-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 138,101 23,992 21.03 4,022 43.81 0.0008
2022-11-14 2022-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 114,109 2,860 2.57 2,796 505.19 0.0006
2022-08-12 2022-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 111,249 -305,638 -73.31 462 -90.38 0.0001
2022-05-13 2022-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 416,887 -12,184 -2.84 4,803 12.17 0.0008
2022-02-08 2021-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 429,071 8,637 2.05 4,282 -22.02 0.0007
2021-11-15 2021-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 420,434 -20,252 -4.60 5,491 -36.37 0.0010
2021-08-13 2021-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 440,686 5,726 1.32 8,629 -6.73 0.0015
2021-05-12 2021-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 434,960 16,038 3.83 9,252 -25.71 0.0017
2021-02-11 2020-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 418,922 -13,898 -3.21 12,454 32.79 0.0024
2020-11-16 2020-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 432,820 -26,903 -5.85 9,379 -8.51 0.0021
2020-08-14 2020-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 459,723 73,375 18.99 10,251 74.31 0.0024
2020-05-14 2020-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 386,348 22,952 6.32 5,881 -29.52 0.0017
2020-02-14 2019-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 363,396 70,310 23.99 8,344 31.86 0.0019
2019-11-13 2019-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 293,086 78,588 36.64 6,328 34.07 0.0015
2019-08-13 2019-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 214,498 -2,568 -1.18 4,720 -20.67 0.0011
2019-05-13 2019-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 217,066 6,190 2.94 5,950 4.96 0.0015
2019-02-12 2018-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 210,876 -918 -0.43 5,669 -8.24 0.0016
2018-11-14 2018-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 211,794 67,575 46.86 6,178 37.01 0.0015
2018-09-18 2018-06-30 13F/A-1 RHYTHM PHARMACEUTICALS COM 76243J105 144,219 53,671 59.27 4,509 150.22 0.0011
2018-08-14 2018-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 131,474 40,926 4,111
2018-05-09 2018-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 90,548 12,367 15.82 1,802 -20.69 0.0005
2018-02-14 2017-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 78,181 78,181 2,272 0.0006
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.