Rhythm CSO sells 7,763 shares in pre-set plan

RHYTHM PHARMACEUTICALS, INC. executive Alastair Garfield, Chief Scientific Officer, reported selling a total of 7,763 shares of common stock on August 13, 2026 in four open‑market or private transactions.

Rhea-AI Filing Summary

RHYTHM PHARMACEUTICALS, INC. executive Alastair Garfield, Chief Scientific Officer, reported selling a total of 7,763 shares of common stock on August 13, 2026 in four open‑market or private transactions. The sales, made under a Rule 10b5-1 trading plan adopted on May 14, 2026, occurred at weighted average prices of $116.1093, $117.0759, $118.2843, and $119.1688 per share, each representing multiple trades within stated price ranges.

Insider Trade Summary 10b5-1

Net Seller: 7,763 shares

Net Sell 4 txns

Insider Garfield Alastair

Role Chief Scientific Officer

Sold 7,763 shs ($913K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	2,007	$116.1093	$233K
Sale	Common Stock F1, F3	1,556	$117.0759	$182K
Sale	Common Stock F1, F4	3,400	$118.2843	$402K
Sale	Common Stock F1, F5	800	$119.1688	$95K

Holdings After Transaction: Common Stock — 2,295 shares (Direct)

Footnotes (5)

1. F1. The sales reported in the Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 14, 2026.
2. F2. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $115.67 to $116.62 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
3. F3. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $116.72 to $117.66 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
4. F4. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $117.73 to $118.71 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
5. F5. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $118.73 to $119.52 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Key Figures

Total shares sold: 7,763 shares Shares sold - first transaction: 2,007 shares Weighted average price - first transaction: $116.1093 per share +4 more

7 metrics

Total shares sold 7,763 shares Aggregate common stock sold across four transactions on August 13, 2026

Shares sold - first transaction 2,007 shares Common stock sale on August 13, 2026 at weighted average price $116.1093

Weighted average price - first transaction $116.1093 per share Multiple trades within $115.67–$116.62 price range

Shares sold - second transaction 1,556 shares Common stock sale on August 13, 2026 at weighted average price $117.0759

Shares sold - third transaction 3,400 shares Common stock sale on August 13, 2026 at weighted average price $118.2843

Shares sold - fourth transaction 800 shares Common stock sale on August 13, 2026 at weighted average price $119.1688

Rule 10b5-1 plan adoption date May 14, 2026 Date Garfield adopted the Rule 10b5-1 trading plan governing these sales

Key Terms

Rule 10b5-1 trading plan, weighted average price, multiple transactions

3 terms

Rule 10b5-1 trading plan regulatory

"The sales reported ... were effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

multiple transactions financial

"The securities were sold in multiple transactions at prices ranging from..."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did RYTM executive Alastair Garfield report on this Form 4?

Alastair Garfield reported selling 7,763 shares of Rhythm Pharmaceuticals common stock on August 13, 2026. The shares were sold in four separate open‑market or private transactions at specified weighted average prices under a pre‑arranged Rule 10b5‑1 trading plan.

At what prices did Alastair Garfield sell RYTM shares on August 13, 2026?

Garfield’s reported sales used weighted average prices of $116.1093, $117.0759, $118.2843, and $119.1688 per share. Footnotes state each average covers multiple transactions within price ranges from $115.67 up to $119.52 per share.

How many RYTM shares did Alastair Garfield sell in each reported transaction?

Garfield sold 2,007 shares, 1,556 shares, 3,400 shares, and 800 shares of Rhythm Pharmaceuticals common stock. All four transactions occurred on August 13, 2026 and are reported as open‑market or private sale transactions of non‑derivative common stock.

Were Alastair Garfield’s RYTM stock sales made under a Rule 10b5-1 plan?

Yes. A footnote states the sales were effected pursuant to a Rule 10b5‑1 trading plan adopted by Garfield on May 14, 2026. The Form 4 also affirms the Rule 10b5‑1 checkbox, indicating trading under a pre‑arranged plan.

Does the Form 4 disclose Alastair Garfield’s remaining RYTM share holdings after these sales?

The reported transactions list no share balance in the "shares following transaction" field for any sale. The Form 4 therefore describes the shares sold and related prices but does not specify Garfield’s remaining holdings in this data excerpt.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

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Available on EDGAR 08/17/2026 - 05:58 PM Accepted by SEC EDGAR 08/17/2026 - 05:57 PM Learn about SEC filing dates

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).

X

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^*

Garfield Alastair

(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 Scientific Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/13/2026

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	08/13/2026		S(1)		2,007	D	$116.1093(2)	8,051	D
Common Stock	08/13/2026		S(1)		1,556	D	$117.0759(3)	6,495	D
Common Stock	08/13/2026		S(1)		3,400	D	$118.2843(4)	3,095	D
Common Stock	08/13/2026		S(1)		800	D	$119.1688(5)	2,295	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

Explanation of Responses:

1. The sales reported in the Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 14, 2026.

2. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $115.67 to $116.62 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

3. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $116.72 to $117.66 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

4. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $117.73 to $118.71 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

5. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $118.73 to $119.52 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

	/s/ Stephen Vander Stoep, attorney-in-fact for Alastair Garfield	08/17/2026
	** 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)