Hunter C. Smith - 01 Feb 2026 Form 4 Insider Report for RHYTHM PHARMACEUTICALS, INC. (RYTM)

Role: Chief Financial Officer
Signature: /s/ Stephen Vander Stoep, attorney-in-fact for Hunter C. Smith
Issuer symbol: RYTM
Transactions as of: 01 Feb 2026
Net transactions value: -$1,171,642
Form type: 4
Filing time: 03 Feb 2026, 16:36:15 UTC
Previous filing: 14 Aug 2025
Next filing: 06 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Smith Hunter C	Chief Financial Officer	C/O RHYTHM PHARMACEUTICALS, INC., 222 BERKELEY STREET, 12TH FLOOR, BOSTON	/s/ Stephen Vander Stoep, attorney-in-fact for Hunter C. Smith	03 Feb 2026	0001636385

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	RYTM	Common Stock	Options Exercise		+26,000	+22%		142,915	01 Feb 2026	Direct	F1
transaction	RYTM	Common Stock	Tax liability	$1,171,642	-10,750	-7.5%	$108.99	132,165	01 Feb 2026	Direct	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	RYTM	Restricted Stock Units	Options Exercise	$0	-4,062	-100%	$0.000000	0	01 Feb 2026	Common Stock	4,062		Direct	F1, F3
transaction	RYTM	Restricted Stock Units	Options Exercise	$0	-4,925	-50%	$0.000000	4,925	01 Feb 2026	Common Stock	4,925		Direct	F1, F4
transaction	RYTM	Restricted Stock Units	Options Exercise	$0	-6,600	-33%	$0.000000	13,200	01 Feb 2026	Common Stock	6,600		Direct	F1, F5
transaction	RYTM	Restricted Stock Units	Options Exercise	$0	-10,413	-25%	$0.000000	31,237	01 Feb 2026	Common Stock	10,413		Direct	F1, F6

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Each restricted stock unit represents a contingent right to receive one share of Issuer common stock.
F2	These shares were withheld for payment of the withholding taxes upon the vesting of the restricted stock units reported herein.
F3	The restricted stock units vest as to 25% of the total shares on each of February 9, 2023, February 9, 2024, February 9, 2025 and February 1, 2026. The restricted stock units have no expiration date.
F4	The restricted stock units vest as to 25% of the total shares on each of February 1, 2024, February 1, 2025, February 1, 2026 and February 1, 2027. The restricted stock units have no expiration date.
F5	The restricted stock units vest as to 25% of the total shares on each of February 16, 2025, February 1, 2026, February 1, 2027 and February 1, 2028. The restricted stock units have no expiration date.
F6	The restricted stock units vest as to 25% of the total shares on each of February 1, 2026, February 1, 2027, February 1, 2028 and February 1, 2029. The restricted stock units have no expiration date.