# EDGAR Filing Document

**Accession Number:** 0000924727
**File Stem:** 0001213900-26-042060
**Filing Date:** 2026-4
**Character Count:** 7345
**Document Hash:** 0f6208f949d534758ce453e65295ddf3
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001213900-26-042060.hdr.sgml**: 20260409

**ACCESSION NUMBER**: 0001213900-26-042060

**CONFORMED SUBMISSION TYPE**: 485BXT

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260409

**DATE AS OF CHANGE**: 20260409

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Investment Managers Series Trust III
- **CENTRAL INDEX KEY:** 0000924727

**ORGANIZATION NAME:**
- **EIN:** 043236699
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 485BXT
- **SEC ACT:** 1940 Act
- **SEC FILE NUMBER:** 811-08544
- **FILM NUMBER:** 26852372

**BUSINESS ADDRESS:**
- **STREET 1:** 235 W. GALENA STREET
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53212
- **BUSINESS PHONE:** 626-385-5777

**MAIL ADDRESS:**
- **STREET 1:** 235 W. GALENA STREET
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53212

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FPA FUNDS TRUST
- **DATE OF NAME CHANGE:** 20021028

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** UAM FUNDS TRUST
- **DATE OF NAME CHANGE:** 19951101

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** REGIS FUND II
- **DATE OF NAME CHANGE:** 19940606
**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Investment Managers Series Trust III
- **CENTRAL INDEX KEY:** 0000924727

**ORGANIZATION NAME:**
- **EIN:** 043236699
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 485BXT
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-79858
- **FILM NUMBER:** 26852371

**BUSINESS ADDRESS:**
- **STREET 1:** 235 W. GALENA STREET
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53212
- **BUSINESS PHONE:** 626-385-5777

**MAIL ADDRESS:**
- **STREET 1:** 235 W. GALENA STREET
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53212

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FPA FUNDS TRUST
- **DATE OF NAME CHANGE:** 20021028

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** UAM FUNDS TRUST
- **DATE OF NAME CHANGE:** 19951101

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** REGIS FUND II
- **DATE OF NAME CHANGE:** 19940606

## Series and Classes Contracts Data

### Mast HedgeIndex Adaptive Equities ETF (Series ID: S000102278)

| Class ID   | Class Name                            | Ticker Symbol   |
|:---|:---|:---|
| C000272747 | Mast HedgeIndex Adaptive Equities ETF |  |

### Mast HedgeIndex Corporate Arbitrage ETF (Series ID: S000102279)

| Class ID   | Class Name                              | Ticker Symbol   |
|:---|:---|:---|
| C000272748 | Mast HedgeIndex Corporate Arbitrage ETF |  |

### Mast HedgeIndex Managed Futures Strategy ETF (Series ID: S000102280)

| Class ID   | Class Name                                   | Ticker Symbol   |
|:---|:---|:---|
| C000272749 | Mast HedgeIndex Managed Futures Strategy ETF |  |

### Mast HedgeIndex Strategic Commodities ETF (Series ID: S000102281)

| Class ID   | Class Name                                | Ticker Symbol   |
|:---|:---|:---|
| C000272750 | Mast HedgeIndex Strategic Commodities ETF |  |

AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON APRIL 9, 2026

REGISTRATION NOS. 033-79858

811-08544

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

**FORM N-1A**

---

| | |
|:---|:---|
| REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 | ☐ |
| PRE-EFFECTIVE AMENDMENT NO. | ☐ |
| POST-EFFECTIVE AMENDMENT NO. 145 | ☒ |
| AND/OR |  |
| REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 | ☐ |
| AMENDMENT NO. 146 | ☒ |

---

**<u>INVESTMENT MANAGERS SERIES TRUST III</u>**

(Exact Name of Registrant as Specified in Charter)

**235 West Galena Street**

**Milwaukee, Wisconsin 53212**

(Address of Principal Executive Offices, including Zip Code)

Registrant's Telephone Number, Including Area Code: (626) 385-5777

Diane J. Drake

Mutual Fund Administration, LLC

2220 E. Route 66, Suite 226

Glendora, California 91740

(Name and Address of Agent for Service)

COPIES TO:

Laurie Anne Dee

Morgan, Lewis & Bockius LLP

600 Anton Boulevard, Suite 1800

Costa Mesa, California 92626

 

*It is proposed that this filing will become effective (check appropriate box):*

☐ immediately upon filing pursuant to paragraph (b) of Rule 485; or

☒ on <u>April 22, 2026,</u> pursuant to paragraph (b) of Rule 485; or

☐ 60 days after filing pursuant to paragraph (a)(1) of Rule 485;

☐ on _______________ pursuant to paragraph (a)(1) of Rule 485; or

☐ 75 days after filing pursuant to paragraph (a)(2) of Rule 485; or

☐ on _______________ pursuant to paragraph (a)(2) of Rule 485; or

☐ on _______________ pursuant to paragraph (a)(3) of Rule 485.

If appropriate, check the following box:

☒ This
post-effective amendment designates a new effective date for a previously filed post-effective amendment.

**Explanatory Note**

This Post-Effective Amendment ("PEA") to the Registration Statement on Form N-1A is being filed for the sole purpose of designating a new effective date for the previously filed PEA No. 137 to the Registrant's Registration Statement filed under Rule 485(a) of the Securities Act of 1933 on January 15, 2026, for the purpose of creating the Mast HedgeIndex Corporate Arbitrage ETF, Mast HedgeIndex Managed Futures Strategy ETF, Mast HedgeIndex Adaptive Equities ETF and Mast HedgeIndex Strategic Commodities ETF, each a new series of the Trust. This PEA incorporates by reference the information contained in [Parts A, B and C of PEA No. 137](https://www.sec.gov/Archives/edgar/data/924727/000121390026004731/ea0272895-01_485apos.htm) to the Registrant's Registration Statement filed on January 15, 2026. The Registrant may file additional subsequent delaying amendments designating a new effective date.

**SIGNATURES**

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this registration statement under rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Milwaukee and State of Wisconsin, on the **<u>9<sup>th</sup> day of April, 2026</u>**.

---

| | |
|:---|:---|
| **INVESTMENT MANAGERS SERIES TRUST III** | **INVESTMENT MANAGERS SERIES TRUST III** |
| By: | /s/ Maureen Quill |
|  | Maureen Quill |
|  | President and Principal Executive Officer |

---

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed on **<u>9<sup>th</sup> day of April, 2026,</u>** by the following persons in the capacities set forth below.

---

| | |
|:---|:---|
| **<u>Signatures</u>** | **<u>Title</u>** |
| /s/ Maureen Quill | Trustee, President & Principal Executive Officer |
| Maureen Quill |  |
| † | Trustee |
| Sandra Brown |  |
| † | Trustee |
| Robert F. Goldrich |  |
| † | Trustee |
| John P. Zader |  |
| | Trustee |
| J. Richard Atwood |  |
| /s/ Rita Dam | Treasurer, Principal Accounting Officer & Principal |
| Rita Dam | Financial Officer |

---

---

| | |
|:---|:---|
| † By: | /s/ Rita Dam |
|  | Rita Dam |
|  | Attorney-in-fact, pursuant to power of attorney previously filed with Post-Effective Amendment No. 127 filed on November 19, 2024. |

---