리듬 파마슈티컬스, Inc.
US ˙ NasdaqGM ˙ US76243J1051

SecurityRYTM / Rhythm Pharmaceuticals, Inc.
InstitutionAlliancebernstein L.p.
Latest Disclosed Ownership910,413 shares
Latest Disclosed Value $ 97,450,608
Alliancebernstein L.p. reports 2.13% decrease in ownership of RYTM / Rhythm Pharmaceuticals, Inc.

On May 15, 2026 - Alliancebernstein L.p. filed a 13F-HR form disclosing ownership of 910,413 shares of Rhythm Pharmaceuticals, Inc. (US:RYTM) valued at $79,178,619 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 930,233 shares of Rhythm Pharmaceuticals, Inc.. This represents a change in shares of -2.13% during the quarter. The current value of the position is $79,761,283 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.

Upgrade to unlock premium data and export to Excel .

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 910,413 -19,820 -2.13 97,451 -2.13 0.0316
2026-02-17 2025-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 930,233 -49,449 -5.05 99,572 0.64 0.0314
2025-11-14 2025-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 979,682 918,212 1,493.76 98,938 2,447.32 0.0312
2025-08-14 2025-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 61,470 0 0.00 3,884 19.29 0.0013
2025-05-15 2025-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 61,470 0 0.00 3,256 -5.38 0.0012
2025-02-12 2024-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 61,470 1,900 3.19 3,441 10.29 0.0012
2024-11-14 2024-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 59,570 -1,500 -2.46 3,121 24.45 0.0010
2024-08-14 2024-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 61,070 7,640 14.30 2,508 8.29 0.0009
2024-05-14 2024-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 53,430 -960 -1.77 2,315 -7.40 0.0008
2024-02-14 2023-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 54,390 0 0.00 2,500 100.64 0.0010
2023-11-14 2023-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 54,390 0 0.00 1,247 39.06 0.0005
2023-08-15 2023-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 54,390 54,390 897 0.0004
2022-08-15 2022-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 0 -44,900 -100.00 0 -100.00
2022-05-13 2022-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 44,900 100 0.22 517 15.66 0.0002
2022-02-14 2021-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 44,800 3,200 7.69 447 -17.68 0.0002
2021-11-10 2021-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 41,600 0 0.00 543 -33.37 0.0002
2021-07-30 2021-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 41,600 0 0.00 815 -7.91 0.0003
2021-05-06 2021-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 41,600 1,500 3.74 885 -25.76 0.0004
2021-02-08 2020-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 40,100 0 0.00 1,192 37.17 0.0006
2020-11-12 2020-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 40,100 -1,200 -2.91 869 -5.65 0.0005
2020-08-13 2020-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 41,300 16,900 69.26 921 148.25 0.0005
2020-05-14 2020-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 24,400 0 0.00 371 -33.75 0.0003
2020-02-18 2019-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 24,400 1,200 5.17 560 11.78 0.0003
2019-11-14 2019-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 23,200 4,500 24.06 501 21.90 0.0003
2019-08-14 2019-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 18,700 3,000 19.11 411 -4.42 0.0003
2019-05-14 2019-03-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 15,700 -900 -5.42 430 -3.59 0.0003
2019-02-13 2018-12-31 13F RHYTHM PHARMACEUTICALS COM 76243J105 16,600 3,900 30.71 446 20.54 0.0003
2018-11-08 2018-09-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 12,700 5,400 73.97 370 62.28 0.0002
2018-08-13 2018-06-30 13F RHYTHM PHARMACEUTICALS COM 76243J105 7,300 7,300 228 0.0002
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.