# EDGAR Filing Document

**Accession Number:** 0001530950
**File Stem:** 0001530950-25-000246
**Filing Date:** 2025-10
**Character Count:** 7517
**Document Hash:** 44ca2f23cdd17507a4526f99a3e4c5a7
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001530950-25-000246.hdr.sgml**: 20251015

**ACCESSION NUMBER**: 0001530950-25-000246

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20251015

**DATE AS OF CHANGE**: 20251015

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Post Holdings, Inc.
- **CENTRAL INDEX KEY:** 0001530950
- **STANDARD INDUSTRIAL CLASSIFICATION:** GRAIN MILL PRODUCTS [2040]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 453355106
- **STATE OF INCORPORATION:** MO
- **FISCAL YEAR END:** 0930

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-86955
- **FILM NUMBER:** 251395616

**BUSINESS ADDRESS:**
- **STREET 1:** 2503 S. HANLEY ROAD
- **CITY:** ST. LOUIS
- **STATE:** MO
- **ZIP:** 63144
- **BUSINESS PHONE:** 314-644-7600

**MAIL ADDRESS:**
- **STREET 1:** 2503 S. HANLEY ROAD
- **CITY:** ST. LOUIS
- **STATE:** MO
- **ZIP:** 63144
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** STIRITZ WILLIAM P
- **CENTRAL INDEX KEY:** 0001052058

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**MAIL ADDRESS:**
- **STREET 1:** C/O POST HOLDINGS, INC.
- **STREET 2:** 2503 S. HANLEY ROAD
- **CITY:** ST LOUIS
- **STATE:** MO
- **ZIP:** 63144

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 3)**

**Post Holdings, Inc.**

*(Name of Issuer)*

**Common Stock, $0.01 par value**

*(Title of Class of Securities)*

**737446104**

*(CUSIP Number)*

**William P. Stiritz**<br>790 Briar Hill Road<br>Belleville IL 62223<br>618-398-7781

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**10/15/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **737446104** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**William P. Stiritz** | Name of reporting person<br>**William P. Stiritz** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**PF** | Source of funds (See Instructions)<br>**PF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**4498836.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**384132.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**4498836.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**384132.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**4882968.00** | Aggregate amount beneficially owned by each reporting person<br>**4882968.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**9.3%** | Percent of class represented by amount in Row (11)<br>**9.3%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The percent ownership information included on line 13 above in this Amendment No. 3 to Schedule 13D is based on 52,604,677 shares of Common Stock, par value $0.01 per share, of Post Holdings, Inc., a Missouri corporation (the "Issuer"), issued and outstanding as of October 15, 2025, according to information provided by the Issuer.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, $0.01 par value

**(b) Name of Issuer:**
Post Holdings, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
2503 S. Hanley Rd, St. Louis, MO, 63144

EXPLANATORY NOTE - This Amendment No. 3 to Schedule 13D relates to the Schedule 13D filed by William P. Stiritz (the "Reporting Person") with the Securities and Exchange Commission (the "SEC") on December 1, 2016 (the "Initial Schedule 13D"), as amended by Amendment No. 1 to Schedule 13D filed with the SEC on February 22, 2021 ("Amendment No. 1") and Amendment No. 2 to Schedule 13D filed with the SEC on February 14, 2025 ("Amendment No. 2" and the Initial Schedule 13D as amended by Amendment No. 1 and Amendment No. 2, the "Schedule 13D"), and amends the Schedule 13D as specifically set forth herein.

**Item 5. Interest in Securities of the Issuer**

**(a)**
Items 5(a)-(e) of the Schedule 13D are hereby amended and restated as follows: As of the date hereof, the Reporting Person beneficially owns, in the aggregate, 4,882,968 shares of Common Stock of the Issuer (the "Common Stock"), representing approximately 9.28% of the Issuer's outstanding shares of Common Stock.
The Reporting Person beneficially owns shares of Common Stock of the Issuer directly (4,329,467 shares) and through The Wildwood Trust, of which the Reporting Person is Trustee (169,369 shares), and through his spouse, Susan Stiritz (384,132 shares).

**(b)**
The number of shares as to which there is sole power to vote or to direct the vote is 4,498,836. The number of shares as to which there is the shared power to vote or to direct the vote is 384,132. The number of shares as to which there is sole power to dispose or to direct the disposition is 4,498,836. The number of shares as to which there is shared power to dispose or to direct the disposition is 384,132. The Reporting Person shares voting and disposition rights with his spouse with respect to 384,132 shares.
Susan Stiritz's address is 790 Briar Hill Road, Belleville, Illinois 62223. Mrs. Stiritz is retired and is a professor of practice emeritus at Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130. During the last five years, Mrs. Stiritz has not been convicted in a criminal proceeding. During the last five years, Mrs. Stiritz has not been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction which resulted in her being subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws. Mrs. Stiritz is a citizen of the United States.

**(c)**
Other than the following, the Reporting Person has effected no transactions in the Common Stock of the Issuer within the past sixty days:
On August 19, 2025, the Reporting Person purchased 36,000 shares of Common Stock of the Issuer in the open market for $109.53 per share.

### 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.

**Reporting Person:** William P. Stiritz

**Signature:** /s/ William P. Stiritz

**Name/Title:** William P. Stiritz

**Date:** 10/15/2025