Mineralys fund sells 104,320 shares at $28.81

The fund reported 7,805,718 shares after the sale; the director disclaims beneficial ownership except to the extent of his pecuniary interest.

Rhea-AI Filing Summary

Mineralys Therapeutics, Inc. (MLYS) director Brian Taylor Slingsby reported that Catalys Pacific Fund, LP sold 104,320 common shares on September 22, 2026, at a weighted-average price of $28.8085 per share. The sales occurred in multiple transactions at prices from $28.700 to $28.905, and the fund held 7,805,718 shares following the sale. Slingsby may be deemed to share voting and investment power over the fund’s shares but disclaims beneficial ownership except to the extent of his pecuniary interest. No Rule 10b5-1 plan is reported.

Insider Trade Summary

Net Seller: 104,320 shares

Net Sell 1 txn

Insider Slingsby Brian Taylor

Role Director

Sold 104,320 shs ($3.01M)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2, F3	104,320	$28.8085	$3.01M

Holdings After Transaction: Common Stock — 7,805,718 shares (Indirect, See footnote)

Footnotes (3)

1. F1. Represents shares of common stock sold by Catalys Pacific Fund, LP. See footnote (3).
2. F2. The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $28.700 to $28.905. 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. Represents shares of common stock held of record by Catalys Pacific Fund, LP. Catalys Pacific Fund GP, LP is the general partner of Catalys Pacific Fund, LP. Catalys Pacific, LLC is the general partner of Catalys Pacific Fund GP, LP, and Mr. Slingsby is the managing partner of Catalys Pacific, LLC. Accordingly, Mr. Slingsby may be deemed to share voting and investment power over the shares held of record by Catalys Pacific Fund, LP. Mr. Slingsby disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein.

Key Figures

Shares sold: 104,320 shares Weighted-average sale price: $28.8085 per share Sale price range: $28.700–$28.905 per share +1 more

4 metrics

Shares sold 104,320 shares September 22, 2026; Catalys Pacific Fund, LP

Weighted-average sale price $28.8085 per share September 22, 2026

Sale price range $28.700–$28.905 per share Multiple transactions on September 22, 2026

Shares following transaction 7,805,718 shares Shares held of record by Catalys Pacific Fund, LP following the sale

Key Terms

weighted-average price, voting and investment power, beneficial ownership, pecuniary interest

4 terms

weighted-average price financial

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

Weighted-average price is the average of multiple prices where each price is counted according to its size or importance—larger trades carry more weight than smaller ones, like averaging course grades by credit hours. It matters to investors because it gives a more realistic picture of the true price paid or received, helping assess trade execution, compare performance, calculate cost basis, and value positions more accurately than a simple average.

voting and investment power regulatory

"may be deemed to share voting and investment power"

beneficial ownership regulatory

"disclaims beneficial ownership of such shares"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"except to the extent of his pecuniary interest therein"

FAQ

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

How many MLYS shares did Catalys Pacific Fund sell, and at what price?

Catalys Pacific Fund, LP sold 104,320 Mineralys Therapeutics common shares on September 22, 2026, at a weighted-average price of $28.8085 per share, across transactions priced from $28.700 to $28.905.

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

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Available on EDGAR 09/24/2026 - 09:50 PM Accepted by SEC EDGAR 09/24/2026 - 09:49 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).

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^*

Slingsby Brian Taylor

(Last) (First) (Middle)

1700 WESTLAKE AVE. N, SUITE 200

THINKSPACE

(Street)

SEATTLE WASHINGTON 98109

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Mineralys Therapeutics, Inc. [ MLYS ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/22/2026

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	09/22/2026		S(1)		104,320	D	$28.8085(2)	7,805,718	I	See footnote(3)

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. Represents shares of common stock sold by Catalys Pacific Fund, LP. See footnote (3).

2. The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $28.700 to $28.905. 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. Represents shares of common stock held of record by Catalys Pacific Fund, LP. Catalys Pacific Fund GP, LP is the general partner of Catalys Pacific Fund, LP. Catalys Pacific, LLC is the general partner of Catalys Pacific Fund GP, LP, and Mr. Slingsby is the managing partner of Catalys Pacific, LLC. Accordingly, Mr. Slingsby may be deemed to share voting and investment power over the shares held of record by Catalys Pacific Fund, LP. Mr. Slingsby disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein.

Remarks:

	/s/ Adam Levy, Attorney-in-fact	09/24/2026
	** 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)