[SCHEDULE 13G/A] Cerus Corp SEC Filing

Rhea-AI Filing Summary

Baker Bros. Advisors and related persons disclosed ownership stakes in Cerus Corporation (CERS) in Amendment No. 11 to a Schedule 13G/A. The filing reports that two Baker Brothers funds (667, L.P. and Baker Brothers Life Sciences, L.P.) beneficially own a combined 12,883,844 shares, representing 6.7% of Cerus based on 191,160,480 shares outstanding as of April 17, 2025. The cover pages show Julian C. Baker and Felix J. Baker each with beneficial ownership of 12,903,708 shares (6.8%), which reflects their direct holdings including 19,864 in-kind distributed shares. The filing states the Adviser has sole voting and dispositive power over the funds' shares. The amendment is signed and dated 08/14/2025.

Positive

• Clear, precise ownership disclosure with exact share counts for Funds and individuals
• Percentage basis disclosed using 191,160,480 shares outstanding as of April 17, 2025
• Adviser authority clarified—Adviser has sole voting and dispositive power over the Funds' shares

Negative

• None.

Insights

Financial Analyst

TL;DR: Routine disclosure showing a meaningful passive stake (6.7%) by Baker Bros. funds; no change-of-control intent stated.

The Schedule 13G/A documents ownership concentrations: the Funds collectively hold 12,883,844 shares (6.7%), and two individuals report 12,903,708 shares (6.8%). The filing follows Rule 13d-1(b)/(c) disclosure practices and affirms the Adviser has sole investment and voting discretion for the Funds. This is a material ownership disclosure for investors monitoring large shareholders, but the filing contains no operational, financial performance or transaction details beyond ownership counts.

Corporate Governance Expert

TL;DR: Ownership structure clarified; Adviser controls voting/dispositive power for the Funds, which is important for governance signal tracking.

The filing clarifies that the Adviser, via management agreements and its GP structure, exercises complete voting and dispositive authority over the Funds' Cerus shares. Signatures from the Adviser, its GP and the individual Bakers formalize the disclosure. The statement includes the outstanding share base used for percentage calculations (191,160,480), supporting transparent governance reporting. No group formation, dissents or plans to influence control are disclosed.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 11)

Cerus Corporation

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

157085101

(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. 157085101

1

Names of Reporting Persons

Baker Bros. Advisors LP

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 12,883,844.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 12,883,844.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,883,844.00

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)

6.7 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. 157085101

1

Names of Reporting Persons

Baker Bros. Advisors (GP) LLC

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 12,883,844.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 12,883,844.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,883,844.00

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)

6.7 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP No. 157085101

1

Names of Reporting Persons

Julian C. Baker

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 12,903,708.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 12,903,708.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,903,708.00

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)

6.8 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP No. 157085101

1

Names of Reporting Persons

Felix J. Baker

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 12,903,708.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 12,903,708.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,903,708.00

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)

6.8 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Cerus Corporation
(b)	Address of issuer's principal executive offices: 1220 Concord Ave, Suite 600 Concord, CA, 94520
Item 2.
(a)	Name of person filing: This Amendment No. 11 is being filed by Baker Bros. Advisors LP (the "Adviser"), Baker Bros. Advisors (GP) LLC (the "Adviser GP"), Julian C. Baker and Felix J. Baker (collectively, the "Reporting Persons").
(b)	Address or principal business office or, if none, residence: The business address of each of the Reporting Persons is: c/o Baker Bros. Advisors LP 860 Washington Street, 3rd Floor New York, NY 10014 (212) 339-5690
(c)	Citizenship: The Adviser is a limited partnership organized under the laws of the State of Delaware. The Adviser GP is a limited liability company organized under the laws of the State of Delaware. The citizenship of each of Julian C. Baker and Felix J. Baker is the United States of America.
(d)	Title of class of securities: Common Stock, par value $0.001 per share
(e)	CUSIP No.: 157085101
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: Items 5 through 9 and 11 of each of the cover pages to this Amendment No. 11 are incorporated herein by reference. Set forth below is the aggregate number of shares of Common Stock ("Common Stock") of Cerus Corporation (the "Issuer") directly held by each of Baker Brothers Life Sciences, L.P. ("Life Sciences") and 667, L.P. ("667", and together with Life Sciences, the "Funds") which may be deemed to be indirectly beneficially owned by the Reporting Persons. Julian C. Baker and Felix J. Baker each also directly holds 19,864 shares of Common Stock of the Issuer previously received from in-kind distributions. The percentage of beneficial ownership for each of the Reporting Persons reported herein and the information set forth below is based on 191,160,480 shares of Common Stock outstanding as of April 17, 2025, as reported in the Issuer's Form 10-Q filed with the Securities and Exchange Commission on May 1, 2025. Such percentage figures are calculated in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). Pursuant to the management agreements, as amended, among the Adviser, the Funds and their respective general partners, the Funds' respective general partners relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds, and thus the Adviser has complete and unlimited discretion and authority with respect to the Funds' investments and voting power over investments. The Adviser GP is the sole general partner of the Adviser. The Adviser GP, Felix J. Baker and Julian C. Baker as managing members of the Adviser GP, and the Adviser may be deemed to be beneficial owners of securities of the Issuer directly held by the Funds.
(b)	Percent of class: The Funds beneficially own 12,883,844 shares of Common Stock or 6.7% of the outstanding Common Stock. 667 beneficially owns 0.6% and Life Sciences beneficially owns 6.1% of the outstanding Common Stock.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 667 directly holds 1,139,770 shares of Common Stock and Life Sciences directly holds 11,744,074 shares of Common Stock.
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 667 directly holds 1,139,770 shares of Common Stock and Life Sciences directly holds 11,744,074 shares of Common Stock.
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
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. The information in Item 4 is incorporated herein by reference.
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

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.

Baker Bros. Advisors LP

Signature:	/s/ Scott L. Lessing
Name/Title:	Scott L. Lessing/ President, Baker Bros. Advisors (GP) LLC, its general partner
Date:	08/14/2025

Baker Bros. Advisors (GP) LLC

Signature:	/s/ Scott L. Lessing
Name/Title:	Scott L. Lessing/ President
Date:	08/14/2025

Julian C. Baker

Signature:	/s/ Julian C. Baker
Name/Title:	Julian C. Baker
Date:	08/14/2025

Felix J. Baker

Signature:	/s/ Felix J. Baker
Name/Title:	Felix J. Baker
Date:	08/14/2025

FAQ

How many Cerus (CERS) shares do Baker Bros. funds report owning?

The filing discloses the Funds beneficially own 12,883,844 shares of Cerus common stock.

What percentage of Cerus does the 12,883,844 shares represent?

That amount represents 6.7% of outstanding common stock based on 191,160,480 shares outstanding.

Do Julian C. Baker and Felix J. Baker hold shares directly in Cerus (CERS)?

Yes. Each is reported with 12,903,708 shares (6.8%), which includes direct holdings of 19,864 shares received in-kind.

Who has voting and dispositive power over the Funds' Cerus shares?

The filing states the Adviser has sole voting and sole dispositive power over the securities held by the Funds.

When was this Schedule 13G/A signed?

The signatures on the amendment are dated 08/14/2025.