Mirum officer plans $4M stock sale after options

Rhea-AI Filing Summary

Mirum Pharmaceuticals, Inc. (MIRM) reports that officer Jolanda Marie Howe has notified of a proposed sale of 40,000 common shares, to be sold for cash on 08/18/2026 through Morgan Stanley Smith Barney, with an aggregate market value of $4,000,000.00, following a stock option exercise. She also reported prior sales of 1,840, 2,721, and 2,594 shares of common stock in June, July, and August 2026, respectively.

Key Figures

Planned shares to be sold: 40,000 shares Aggregate market value of planned sale: $4,000,000.00 Shares sold on 08/03/2026: 1,840 shares +5 more

8 metrics

Planned shares to be sold 40,000 shares Common stock sale planned for 08/18/2026

Aggregate market value of planned sale $4,000,000.00 Value for 40,000 Mirum common shares to be sold

Shares sold on 08/03/2026 1,840 shares Common stock sold by Jolanda Marie Howe

Proceeds on 08/03/2026 sale $193,733.60 Sale of 1,840 Mirum common shares

Shares sold on 07/01/2026 2,721 shares Common stock sold by Jolanda Marie Howe

Proceeds on 07/01/2026 sale $326,520.00 Sale of 2,721 Mirum common shares

Shares sold on 06/17/2026 2,594 shares Common stock sold by Jolanda Marie Howe

Proceeds on 06/17/2026 sale $264,458.30 Sale of 2,594 Mirum common shares

Key Terms

Rule 144, Stock Option Exercise, aggregate market value, Securities To Be Sold

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Stock Option Exercise financial

"Common | 08/18/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

aggregate market value financial

"Common | Morgan Stanley Smith Barney LLC ... | 40000 | 4000000.00"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

Securities To Be Sold regulatory

"144: Securities To Be Sold Common | 08/18/2026"

FAQ

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

What does this Form 144 disclose about Mirum Pharmaceuticals, Inc. (MIRM)?

It discloses that officer Jolanda Marie Howe plans to sell 40,000 common shares of Mirum Pharmaceuticals, Inc. on 08/18/2026 following a stock option exercise, with an aggregate market value of $4,000,000.00.

How many MIRM shares is Jolanda Marie Howe planning to sell and when?

Jolanda Marie Howe plans to sell 40,000 common shares of MIRM on 08/18/2026. The sale is tied to a stock option exercise and is to be executed for cash through Morgan Stanley Smith Barney.

What is the aggregate market value of the proposed MIRM share sale?

The proposed sale involves an aggregate market value of $4,000,000.00 for 40,000 common shares of Mirum Pharmaceuticals, Inc. The transaction is planned for 08/18/2026 on NASDAQ following a stock option exercise.

Which broker is handling the planned MIRM share sale for Jolanda Marie Howe?

The planned sale will be handled by Morgan Stanley Smith Barney LLC Executive Financial Services. The broker’s listed address is 1 New York Plaza, 8th Floor, New York, NY 10004, and the transaction relates to 40,000 Mirum common shares.

What MIRM share sales has Jolanda Marie Howe made in the past three months?

She reported selling 1,840 shares on 08/03/2026 for $193,733.60, 2,721 shares on 07/01/2026 for $326,520.00, and 2,594 shares on 06/17/2026 for $264,458.30, all in Mirum common stock.

What is the nature of the securities transaction reported for MIRM on 08/18/2026?

The transaction is described as a Stock Option Exercise for Mirum common stock. The resulting 40,000 shares are to be sold for cash on 08/18/2026 through Morgan Stanley Smith Barney.

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

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Available on EDGAR 08/18/2026 - 05:25 PM Accepted by SEC EDGAR 08/18/2026 - 05:24 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001974200
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	MIRUM PHARMACEUTICALS, INC.
SEC File Number	001-38981
Address of Issuer	989 East Hillsdale Boulevard, Suite 300 Foster City CALIFORNIA 94404
Phone	(650) 667-4085
Name of Person for Whose Account the Securities are To Be Sold	JOLANDA MARIE HOWE
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	40000	4000000.00	64932203	08/18/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/18/2026	Stock Option Exercise	Issuer			40000	08/18/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
JOLANDA MARIE HOWE 989 East Hillsdale Boulevard, Suite 300 Foster City CA 94404	Common	08/03/2026	1840	193733.60
JOLANDA MARIE HOWE 989 East Hillsdale Boulevard, Suite 300 Foster City CA 94404	Common	07/01/2026	2721	326520.00
JOLANDA MARIE HOWE 989 East Hillsdale Boulevard, Suite 300 Foster City CA 94404	Common	06/17/2026	2594	264458.30

144: Remarks and Signature

Remarks
Date of Notice	08/18/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Jolanda Howe
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)