Janus Henderson Reports ~946K Shares in OmniAb (OABI) — Schedule 13G/A

Rhea-AI Filing Summary

Janus Henderson Group plc reports a small, passive holding in OmniAb, Inc.'s common stock, amounting to roughly 945,956 shares which the filing states represents 0.8% of the class. The disclosure shows the firm has shared voting and dispositive power over these shares (no sole voting or dispositive power reported), and the filing identifies indirect subsidiaries (JHIUS, JHIUKL and JHIAIFML) as registered investment advisers providing advice to managed portfolios.

The filing includes a certification that the securities are held in the ordinary course of business and not for the purpose of changing or influencing control of the issuer. The filing also includes a power of attorney authorizing designated compliance officers to execute ownership reports on the company's behalf.

Insights

Securities Analyst

TL;DR: Routine institutional disclosure showing a sub-5% passive stake (0.8%), limited investor control — minimal market impact.

The Schedule 13G/A reflects a non-controlling holding by Janus Henderson Group plc in OmniAb, reporting approximately 945,956 shares and shared voting/dispositive authority. From an investor-impact perspective, holdings below 5% reported on a 13G are typically passive and indicate no intent to influence corporate control. The disclosure lists indirect subsidiaries that act as registered investment advisers to managed portfolios, which explains the shared-power entries. This filing is procedural and does not signal a change in management or a material strategic stake.

Corporate Governance Expert

TL;DR: Governance implications are limited — shared power and an explicit ordinary-course certification point to passive stewardship.

The document documents shared voting and dispositive power rather than sole control, and the certification affirms the position is held in the ordinary course of business, not to influence control. For boards and governance watchers, a 0.8% disclosed stake via Schedule 13G/A typically does not trigger heightened engagement expectations or require defensive actions. The inclusion of a power of attorney for compliance filings is standard practice for large asset managers and confirms delegated filing authority rather than a governance change at the issuer.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 4)

OMNIAB, INC.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

68218J103

(CUSIP Number)

06/30/2025

(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. 68218J103

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 948,434.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 948,434.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

948,434.00

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)

0.8 %

12

Type of Reporting Person (See Instructions)

IA, HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: OMNIAB, INC.
(b)	Address of issuer's principal executive offices: 5980 HORTON STREET, SUITE 600 EMERYVILLE, CA 94608
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.: 68218J103
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: JHIUS may be deemed to be the beneficial owner of 945,956 shares
(b)	Percent of class: 0.8 %
(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: 945956
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 945956
Item 5.	Ownership of 5 Percent or Less of a Class.
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. N/A
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. JHIUS, JHIUKL and JHIAIFML are indirect subsidiaries of Janus Henderson and are registered investment advisers furnishing investment advice to Managed Portfolios.
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, CCO
Date:	08/14/2025

Exhibit Information

POWER OF ATTORNEY The undersigned, Janus Henderson Group plc ("the Company"), does hereby make, constitute and appoint each of Kristin Mariani and Caroline Barotti acting severally, as its true and lawful attorneys in-fact, for the purpose of, from time to time, executing in its name and on its behalf, whether the Company individually or as representative of others, any and all documents, certificates, instruments, statements, other filings and amendments to the foregoing (collectively, "documents") determined by such person to be necessary or appropriate to comply with ownership or control-person reporting requirements imposed by any United States or non-United States governmental or regulatory authority, including, without limitation, Forms 13D, 13F, 13G and 13H and any amendments to any of the foregoing as may be required to be filed with the Securities and Exchange Commission, and delivering, furnishing or filing any such documents with the appropriate governmental, regulatory authority or other person, and giving and granting to each such attorney-in-fact power and authority to act in the premises as fully and to all intents and purposes as the Company might or could do if personally present by one of its authorized signatories, hereby ratifying and confirming all that said attorney-in-fact shall lawfully do or cause to be done by virtue hereof. Any such determination by an attorney-in-fact named herein shall be conclusively evidenced by such person's execution, delivery, furnishing or filing of the applicable document. This power of attorney shall be valid from the date hereof and shall remain in full force and effect until either revoked in writing by the Company, or, in respect of any attorney-in-fact named herein, until such person ceases to be an employee of the Company or one of its affiliates. IN WITNESS WHEREOF, the undersigned has caused this power of attorney to be executed as of this 9th day of December, 2022. Janus Henderson Group plc By: /s/ Michelle Rosenberg Name: Michelle Rosenberg Title: General Counsel and Company Secretary

FAQ

How many OmniAb (OABI) shares does Janus Henderson report owning?

The filing reports approximately 945,956 shares beneficially owned by Janus Henderson-related persons (the filing also shows an aggregate figure of 948,434 elsewhere in the document).

What percentage of OmniAb does Janus Henderson's holding represent?

The filing states the position represents 0.8% of the class.

Does Janus Henderson have sole voting or dispositive power over these OABI shares?

No. The filing reports 0 shares of sole voting or dispositive power and shared voting/dispositive power over the reported shares.

Are the shares held to influence control of OmniAb?

No. The certification states the securities are held in the ordinary course of business and not for the purpose of changing or influencing control.

Which Janus Henderson entities are tied to this filing?

Indirect subsidiaries JHIUS, JHIUKL and JHIAIFML are identified as registered investment advisers furnishing advice to managed portfolios and are related to the reported ownership.