[SCHEDULE 13G/A] POST HOLDINGS, INC. SEC Filing

Rhea-AI Filing Summary

Route One Investment Company, L.P., together with affiliated entities and two named reporting persons, disclose beneficial holdings in Post Holdings, Inc. totaling 3,413,918 shares, representing 6.1% of the outstanding common stock based on 55,718,597 shares outstanding. The filing breaks ownership across related entities: the Master Fund holds 2,354,619 shares (4.2%) while Route One and its U.S.-organized affiliates are reported at the 6.1% level.

The statement shows these shares are held with shared voting and dispositive power rather than sole control for most entities; one affiliate reports sole voting power for the same 3,413,918-share amount while dispositive power is shared. The reporting persons state the securities were acquired and are held in the ordinary course of business and expressly disclaim that the holdings were acquired to change or influence control of the issuer.

Insights

Financial Analyst

TL;DR Route One and affiliates report a material >5% stake (3.41M shares) in POST, disclosed as ordinary-course holdings with shared voting power.

The filing identifies a combined beneficial position of 3,413,918 shares (6.1%), a level that can attract investor attention because holdings above 5% must be publicly reported and can affect float and ownership concentration metrics. The split between the Master Fund (2,354,619 shares) and other Route One entities clarifies internal allocation but shows the economic exposure is concentrated within a related group. Reported shared voting and dispositive power suggest influence is coordinated but not unilateral; the filing also includes explicit disclaimers that the position is not intended to change or influence control. For shareholders, this disclosure updates ownership registers and could be relevant for liquidity and potential activist signaling, though no activist intent is stated.

Corporate Governance Expert

TL;DR A 6.1% beneficial stake with shared voting power is material disclosure but the filing disclaims any intent to influence control.

The statement documents governance-related facts: ownership percentages, allocation across parent/affiliate entities, and the nature of voting/dispositive authority. Notably, the reporting persons repeatedly disclaim group membership and beneficial ownership beyond pecuniary interest and certify the holdings were acquired in the ordinary course and not to alter control. From a governance perspective, the presence of shared voting power and a public joint filing agreement suggests coordination on disclosure rather than an immediate change in board or control dynamics. This filing is therefore material for transparency but does not, on its face, indicate an imminent governance contest.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 9)

Post Holdings, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

737446104

(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. 737446104

1

Names of Reporting Persons

Route One Investment Company, L.P.

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 0.00
6	Shared Voting Power 3,413,918.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,413,918.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,413,918.00

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)

6.1 %

12

Type of Reporting Person (See Instructions)

IA, PN

Comment for Type of Reporting Person: Percentage calculated based on 55,718,597 shares of Common Stock outstanding on May 5, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2025.

SCHEDULE 13G

CUSIP No. 737446104

1

Names of Reporting Persons

ROIC, 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 0.00
6	Shared Voting Power 3,413,918.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,413,918.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,413,918.00

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)

6.1 %

12

Type of Reporting Person (See Instructions)

HC, OO

Comment for Type of Reporting Person: Percentage calculated based on 55,718,597 shares of Common Stock outstanding on May 5, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2025.

SCHEDULE 13G

CUSIP No. 737446104

1

Names of Reporting Persons

Route One Investment Company, 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 3,413,918.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,413,918.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,413,918.00

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)

6.1 %

12

Type of Reporting Person (See Instructions)

HC, OO

Comment for Type of Reporting Person: Percentage calculated based on 55,718,597 shares of Common Stock outstanding on May 5, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2025.

SCHEDULE 13G

CUSIP No. 737446104

1

Names of Reporting Persons

Route One Offshore Master Fund, L.P.

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

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,354,619.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,354,619.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,354,619.00

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)

4.2 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Percentage calculated based on 55,718,597 shares of Common Stock outstanding on May 5, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2025.

SCHEDULE 13G

CUSIP No. 737446104

1

Names of Reporting Persons

William F. Duhamel, Jr.

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 0.00
6	Shared Voting Power 3,413,918.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,413,918.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,413,918.00

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)

6.1 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: Percentage calculated based on 55,718,597 shares of Common Stock outstanding on May 5, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2025.

SCHEDULE 13G

CUSIP No. 737446104

1

Names of Reporting Persons

Jason E. Moment

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 0.00
6	Shared Voting Power 3,413,918.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,413,918.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,413,918.00

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)

6.1 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: Percentage calculated based on 55,718,597 shares of Common Stock outstanding on May 5, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2025.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Post Holdings, Inc.
(b)	Address of issuer's principal executive offices: 2503 S. Hanley Road, St. Louis, MO 63144
Item 2.
(a)	Name of person filing: Route One Investment Company, L.P. ("Route One") ROIC, LLC Route One Investment Company, LLC (the "General Partner") Route One Offshore Master Fund, L.P. (the "Master Fund") William F. Duhamel, Jr. Jason E. Moment Route One is the investment adviser to investment funds, including the Master Fund (collectively, the "Funds"), and the General Partner is the general partner of one or more of those funds. ROIC, LLC is the general partner of Route One. Mr. Duhamel and Mr. Moment are the control persons of Route One, ROIC, LLC and the General Partner. The reporting persons are filing this Schedule 13G jointly, but not as members of a group, and each disclaims membership in a group. Each reporting person also disclaims beneficial ownership of the Common Stock except to the extent of that person's pecuniary interest therein. In addition, the filing of this Schedule 13G on behalf of the Master Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any Common Stock covered by this Schedule 13G.
(b)	Address or principal business office or, if none, residence: The principal business office of the reporting persons other than the Master Fund is: One Letterman Drive, Building D, Suite DM 200, San Francisco, CA 94129 The principal business office of the Master Fund is: c/o Citco Fund Services (Cayman Islands) Limited, 89 Nexus Way, Camana Bay, P.O. Box 31106SMB, Grand Cayman, Cayman Islands
(c)	Citizenship: See Item 4 of the cover sheet for each reporting person.
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 737446104
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: Route One: 3,413,918 ROIC, LLC: 3,413,918 General Partner: 3,413,918 Master Fund: 2,354,619 William F. Duhamel, Jr.: 3,413,918 Jason E. Moment: 3,413,918
(b)	Percent of class: Route One: 6.1% ROIC, LLC: 6.1% General Partner: 6.1% Master Fund: 4.2% William F. Duhamel, Jr.: 6.1% Jason E. Moment: 6.1%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Route One: 0 ROIC, LLC: 0 General Partner: 0 Master Fund: 0 William F. Duhamel, Jr.: 0 Jason E. Moment: 0
	(ii) Shared power to vote or to direct the vote: Route One: 3,413,918 ROIC, LLC: 3,413,918 General Partner: 3,413,918 Master Fund: 2,354,619 William F. Duhamel, Jr.: 3,413,918 Jason E. Moment: 3,413,918
	(iii) Sole power to dispose or to direct the disposition of: Route One: 0 ROIC, LLC: 0 General Partner: 0 Master Fund: 0 William F. Duhamel, Jr.: 0 Jason E. Moment: 0
	(iv) Shared power to dispose or to direct the disposition of: Route One: 3,413,918 ROIC, LLC: 3,413,918 General Partner: 3,413,918 Master Fund: 2,354,619 William F. Duhamel, Jr.: 3,413,918 Jason E. Moment: 3,413,918
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 Funds hold the Common Stock for the benefit of their investors and have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Common Stock. No individual Fund's holdings of Common Stock are more than five percent of the outstanding Common Stock.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
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. By signing below I certify that, to the best of my knowledge and belief, the securities referred to above 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.

Route One Investment Company, L.P.

Signature:	/s/ Jason E. Moment
Name/Title:	Managing Member of the General Partner, ROIC, LLC
Date:	08/13/2025

ROIC, LLC

Signature:	/s/ Jason E. Moment
Name/Title:	Managing Member
Date:	08/13/2025

Route One Investment Company, LLC

Signature:	/s/ Jason E. Moment
Name/Title:	Managing Member
Date:	08/13/2025

Route One Offshore Master Fund, L.P.

Signature:	/s/ Jason E. Moment
Name/Title:	Managing Member of the General Partner, Route One Investment Company, LLC
Date:	08/13/2025

William F. Duhamel, Jr.

Signature:	/s/ William F. Duhamel, Jr.
Name/Title:	Reporting person
Date:	08/13/2025

Jason E. Moment

Signature:	/s/ Jason E. Moment
Name/Title:	Reporting person
Date:	08/13/2025

Exhibit Information

Ex. 99 - Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G