Janus Henderson holds 11.8% of Mirum Pharmaceuticals (MIRM) shares

Rhea-AI Filing Summary

Janus Henderson Group plc, through its investment adviser subsidiaries, reports beneficial ownership of 6,065,308 shares of Mirum Pharmaceuticals, Inc. common stock, representing 11.8% of the class as of 12/31/2025.

The shares are held in various managed portfolios, where Janus Henderson’s asset managers exercise shared voting and dispositive power but do not have rights to receive dividends or sale proceeds. The filing states the position is held in the ordinary course of business and not for the purpose of changing or influencing control of Mirum Pharmaceuticals.

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Accepted by SEC EDGAR 02/17/2026 - 04:33 PM Learn about SEC filing dates

FAQ

What ownership stake does Janus Henderson report in Mirum Pharmaceuticals (MIRM)?

Janus Henderson reports beneficial ownership of 6,065,308 Mirum Pharmaceuticals common shares, representing 11.8% of the outstanding class. This stake is held across multiple managed portfolios where Janus Henderson’s asset managers exercise shared voting and investment discretion on behalf of their clients.

Who actually holds the Mirum Pharmaceuticals (MIRM) shares reported by Janus Henderson?

The Mirum shares are held in Janus Henderson-managed portfolios, including investment companies and separate accounts. Janus Henderson’s adviser subsidiaries exercise investment and voting discretion, while the underlying managed portfolios retain rights to dividends and sale proceeds from the Mirum Pharmaceuticals securities.

Does Janus Henderson have sole voting or dispositive power over Mirum Pharmaceuticals (MIRM) shares?

No, the filing reports zero shares with sole voting or dispositive power. Janus Henderson’s asset managers have shared voting power and shared dispositive power over 6,065,308 Mirum Pharmaceuticals common shares through their managed portfolios, reflecting their discretionary authority for those client accounts.

Is any single Janus Henderson-managed portfolio over 5% of Mirum Pharmaceuticals (MIRM)?

No individual managed portfolio exceeds 5% of Mirum Pharmaceuticals’ common stock. The filing states that none of the separate managed portfolios own more than five percent of the issuer’s common shares, even though Janus Henderson’s aggregated beneficial ownership totals 11.8% of the class.

Why is Janus Henderson filing an amended Schedule 13G on Mirum Pharmaceuticals (MIRM)?

The amended Schedule 13G updates Janus Henderson’s beneficial ownership information for Mirum Pharmaceuticals as of December 31, 2025. It confirms the aggregated 11.8% stake, the shared voting and dispositive powers, and that the holdings are maintained in the ordinary course of business without control intent.

Does Janus Henderson seek to influence control of Mirum Pharmaceuticals (MIRM)?

The certification states the Mirum Pharmaceuticals securities were acquired and are held in the ordinary course of business. It further states they were not acquired and are not held for changing or influencing control of the issuer, nor in connection with any control-related transaction.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 7)

MIRUM PHARAMACEUTICALS, INC.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

604749101

(CUSIP Number)

12/31/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 604749101

1

Names of Reporting Persons

JANUS HENDERSON GROUP PLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

JERSEY

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 6,065,308.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 6,065,308.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

6,065,308.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

11.8 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MIRUM PHARAMACEUTICALS, INC.
(b)	Address of issuer's principal executive offices: 989 EAST HILLSDALE BOULEVARD, SUITE 300 FOSTER CITY, CA 94404
Item 2.
(a)	Name of person filing: Janus Henderson Group plc
(b)	Address or principal business office or, if none, residence: 201 Bishopsgate EC2M 3AE, United Kingdom
(c)	Citizenship: Y9
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 604749101
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: Janus Henderson Group plc (JHG) is the ultimate parent of a number of SEC-registered investment advisers and foreign equivalents thereof, including but not limited to Janus Henderson Investors US LLC, Janus Henderson Investors UK Limited, Janus Henderson Investors Australia Institutional Funds Management Limited, Janus Henderson Investors Middle East Limited, Janus Henderson Investors (Jersey) Limited, Janus Henderson Investors (Japan) Limited, Janus Henderson Investors (Singapore) Limited, Kapstream Capital Pty Limited, Privacore Capital Advisors LLC, Tabula Investment Management Limited, and Victory Park Capital Advisors LLC (each, an Asset Manager and together, the Asset Managers). The Asset Managers generally exercise investment and/or voting discretion on behalf of their clients which include investment companies, other investment advisers, institutional separate accounts and retail separate accounts (collectively referred to herein as Managed Portfolios). As a result of their exercise of investment and/or voting discretion on behalf of the Managed Portfolios, the Asset Managers may be deemed to be the beneficial owner of 6,065,308 common stock of Mirum Pharmaceuticals, Inc. However, the Asset Managers do not have the right to receive any dividends from, or the proceeds from the sale of, the securities held in the Managed Portfolios and disclaim any ownership associated with such rights.
(b)	Percent of class: 11.8 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 6065308
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 6065308
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. The Managed Portfolios have the right to receive all dividends from, and the proceeds from the sale of, the securities held in their respective accounts. Of the Managed Portfolios, none own more than five percent of the common stock of Mirum Pharmaceuticals, Inc.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Please refer to Exhibit 99.
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. N/A
Item 9.	Notice of Dissolution of Group.
	Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5. N/A

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

JANUS HENDERSON GROUP PLC

Signature:	Kristin Mariani
Name/Title:	Head of North America Compliance
Date:	02/17/2026

Exhibit Information

Exhibit 24: Power of Attorney Exhibit 99: Item 7