[Form 4] RHYTHM PHARMACEUTICALS, INC. Insider Trading Activity

Rhea-AI Filing Summary

Rhythm Pharmaceuticals Chief Financial Officer Hunter C. Smith exercised stock options for 3,000 shares of Common Stock at an exercise price of $17.87 per share. This moved 3,000 shares from options into directly held stock, with no shares reported sold in this filing.

Following the transaction, Smith directly owns 119,611 shares of Common Stock and 79,000 stock options that remain outstanding and fully vested. The exercised options were already fully vested, indicating this was a routine conversion of derivative awards into common shares rather than an open-market purchase or sale.

Insider Trade Summary

3,000 shares exercised/converted

Mixed 2 txns

Insider Smith Hunter C

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Exercise	Stock Options (Right to Buy)	3,000	$0.00	--
Exercise	Common Stock	3,000	$17.87	$54K

Holdings After Transaction: Stock Options (Right to Buy) — 79,000 shares (Direct, null); Common Stock — 119,611 shares (Direct, null)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Smith Hunter C

(Last) (First) (Middle)

C/O RHYTHM PHARMACEUTICALS, INC.

222 BERKELEY STREET, 12TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
RHYTHM PHARMACEUTICALS, INC. [ RYTM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/18/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/18/2026		M		3,000	A	$17.87	119,611	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (Right to Buy)	$17.87	05/18/2026		M			3,000	(1)	02/13/2030	Common Stock	3,000	$0	79,000	D

Explanation of Responses:

1. The options are fully vested.

	/s/ Stephen Vander Stoep, attorney-in-fact for Hunter C. Smith	05/20/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Rhythm Pharmaceuticals (RYTM) report for Hunter C. Smith?

Rhythm Pharmaceuticals reported that CFO Hunter C. Smith exercised stock options for 3,000 shares of Common Stock. The transaction converted vested options into directly held shares and did not involve any reported open-market purchases or sales in this Form 4.

At what price did the Rhythm Pharmaceuticals (RYTM) CFO exercise stock options?

Hunter C. Smith exercised 3,000 stock options at an exercise price of $17.87 per share. This price reflects the pre-set option strike, not the prevailing market price. The options were fully vested at the time of exercise, indicating a routine compensation-related event.

How many Rhythm Pharmaceuticals (RYTM) shares does the CFO hold after this Form 4?

After exercising options, CFO Hunter C. Smith directly holds 119,611 shares of Rhythm Pharmaceuticals Common Stock. He also retains 79,000 stock options outstanding. This context shows the 3,000-share exercise is small relative to his overall equity position in the company.

Did the Rhythm Pharmaceuticals (RYTM) CFO sell any shares in this Form 4 filing?

No shares were reported sold by CFO Hunter C. Smith in this Form 4. The filing only shows an option exercise converting 3,000 stock options into 3,000 shares of Common Stock, with no accompanying sale, tax withholding, or gift transactions disclosed.

What is the status of the Rhythm Pharmaceuticals (RYTM) stock options exercised by the CFO?

The Form 4 notes that the exercised stock options were fully vested. Fully vested options are already earned and exercisable, so converting them into shares is a standard step in realizing equity compensation rather than a new grant or market-based share purchase.