Mirum (MIRM) Files Form 144 for 17,000-Share Sale via Morgan Stanley

Rhea-AI Filing Summary

Mirum Pharmaceuticals (MIRM) filed a Form 144 notifying a proposed sale of securities. The filing shows 17,000 common shares to be sold through Morgan Stanley Smith Barney on NASDAQ with an aggregate market value of $1,309,715.70 and total shares outstanding listed as 50,237,647. The securities were acquired and are proposed to be sold on 09/08/2025 via a stock option exercise, with cash payment recorded. The filer reports no securities sold in the past three months for the account. The notice includes the required representation that the seller is not aware of undisclosed material adverse information.

Positive

• Full transaction details provided: number of shares (17,000), aggregate value ($1,309,715.70), broker (Morgan Stanley Smith Barney) and exchange (NASDAQ)
• Acquisition and payment method disclosed: acquired by stock option exercise on 09/08/2025 with cash payment
• No sales in prior three months reported for the account, aiding Rule 144 aggregation clarity
• Seller attestation included that they do not know undisclosed material adverse information

Negative

• None.

Insights

Securities Analyst

TL;DR: Routine Rule 144 notice for an insiders' sale following option exercise; disclosure provides size and timing but no new company fundamentals.

The filing documents a proposed sale of 17,000 shares valued at $1,309,715.70, executed through Morgan Stanley Smith Barney and to be traded on NASDAQ. The shares were acquired by stock option exercise on the same date as the proposed sale, with cash payment to the issuer. The filer indicates no sales in the prior three months, which is relevant for Rule 144 aggregation and volume calculations. This is a procedural disclosure rather than a fundamental change to the issuer's business or financial condition.

Corporate Governance Expert

TL;DR: Compliance-focused filing showing the seller's attestation and transaction mechanics; typical governance transparency.

The Form 144 includes the seller's representation that they are unaware of undisclosed material adverse information and records transaction mechanics: acquisition by option exercise and cash payment, broker identity, and planned sale date. It satisfies Rule 144 notice requirements and provides investors with clear information on insider selling mechanics without introducing new governance issues or disclosures.

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

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

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

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	17000	1309715.70	50237647	09/08/2025	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	09/08/2025	Stock Option Exercise	Issuer			17000	09/08/2025	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

Nothing to Report

144: Remarks and Signature

Remarks

Date of Notice

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

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does Mirum Pharmaceuticals' (MIRM) Form 144 disclose?

It discloses a proposed sale of 17,000 common shares valued at $1,309,715.70 to be executed on NASDAQ through Morgan Stanley Smith Barney.

How were the shares acquired for the MIRM Form 144 filing?

The shares were acquired via stock option exercise on 09/08/2025, and payment was made in cash to the issuer.

Does the Form 144 report any sales by this person in the past three months?

No. The filing states "Nothing to Report" for securities sold during the past three months.

What is the aggregate market value and outstanding shares reported?

Aggregate market value: $1,309,715.70. Shares outstanding: 50,237,647 as listed in the filing.

Which broker and exchange are named in the Form 144?

Broker: Morgan Stanley Smith Barney LLC Executive Financial Services. Exchange: NASDAQ.