Stuart A. Arbuckle - 23 Jun 2026 Form 4 Insider Report for RHYTHM PHARMACEUTICALS, INC. (RYTM)

Reporting relationship: Director
Issuer ticker: RYTM
Reported as of: 23 Jun 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 25 Jun 2026, 18:03:05 UTC
Prior SEC filing: 12 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Stephen Vander Stoep, attorney-in-fact for Stuart A. Arbuckle

Key filing fact

Stuart A. Arbuckle filed Form 4 for RHYTHM PHARMACEUTICALS, INC. (RYTM) on 25 Jun 2026.

Key facts

This page summarizes Stuart A. Arbuckle's Form 4 filing for RHYTHM PHARMACEUTICALS, INC. (RYTM).
4 reported transactions and 3 derivative rows are listed below.
Accepted by SEC: 25 Jun 2026, 18:03.

Change

Previous filing in this sequence was filed on 12 Jun 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001557290 Primary reporting owner

Arbuckle Stuart A

Relationship: Director
Address: C/O RHYTHM PHARMACEUTICALS, INC., 222 BERKELEY STREET, 12TH FLOOR, BOSTON
Signature: /s/ Stephen Vander Stoep, attorney-in-fact for Stuart A. Arbuckle
Signature date: 25 Jun 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

RYTM transaction

Common Stock

Options Exercise

Transaction value
Shares: +4,712
Change %: +67%
Price
Shares after: 11,712
Date: 23 Jun 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

RYTM transaction Derivative

Restricted Stock Units

Options Exercise

Transaction value
Shares: -4,712
Change %: -100%
Price: $0.000000^*
Shares after: 0
Date: 23 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 4,712
Exercise price
Footnotes: F1, F2

RYTM transaction Derivative

Stock Option (right to buy)

Award

Transaction value
Shares: +3,691
Change %
Price: $0.000000^*
Shares after: 3,691
Date: 24 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 3,691
Exercise price: $107.55
Footnotes: F3

RYTM transaction Derivative

Restricted Stock Units

Award

Transaction value
Shares: +2,324
Change %
Price: $0.000000^*
Shares after: 2,324
Date: 24 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 2,324
Exercise price
Footnotes: F1, F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 4 footnotes

Footnote F1

Each restricted stock unit represents a contingent right to receive one share of Issuer common stock.

Footnote F2

The restricted stock units are fully vested. The restricted stock units have no expiration date.

Footnote F3

The options fully vest upon the earlier of (i) June 24, 2027 or (ii) the day immediately prior to the date of the Issuer's next annual meeting of the stockholders to be held in 2027, subject to the Reporting Person's continued service on such vesting date.

Footnote F4

The restricted stock units fully vest upon the earlier of (i) June 24, 2027 or (ii) the day immediately prior to the date of the Issuer's next annual meeting of the stockholders to be held in 2027, subject to the Reporting Person's continued service on such vesting date. The restricted stock units have no expiration date.