# EDGAR Filing Document

**Accession Number:** 0001079575
**File Stem:** 0001104659-26-075885
**Filing Date:** 2026-6
**Character Count:** 7790
**Document Hash:** 2c9ba79aa089feaae3b72ac890ae99c8
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-075885.hdr.sgml**: 20260618

**ACCESSION NUMBER**: 0001104659-26-075885

**CONFORMED SUBMISSION TYPE**: 485BXT

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260618

**DATE AS OF CHANGE**: 20260618

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CALAMOS ADVISORS TRUST/IL
- **CENTRAL INDEX KEY:** 0001079575

**ORGANIZATION NAME:**
- **EIN:** 367271106
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 485BXT
- **SEC ACT:** 1940 Act
- **SEC FILE NUMBER:** 811-09237
- **FILM NUMBER:** 261104142

**BUSINESS ADDRESS:**
- **STREET 1:** 2020 CALAMOS COURT
- **STREET 2:** C/O CALAMOS ADVISORS LLC
- **CITY:** NAPERVILLE
- **STATE:** IL
- **ZIP:** 60563
- **BUSINESS PHONE:** 6302451046

**MAIL ADDRESS:**
- **STREET 1:** 2020 CALAMOS COURT
- **STREET 2:** C/O CALAMOS ADVISORS LLC
- **CITY:** NAPERVILLE
- **STATE:** IL
- **ZIP:** 60563

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CALAMOS INSURANCE TRUST
- **DATE OF NAME CHANGE:** 19990212
**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CALAMOS ADVISORS TRUST/IL
- **CENTRAL INDEX KEY:** 0001079575

**ORGANIZATION NAME:**
- **EIN:** 367271106
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 485BXT
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-72511
- **FILM NUMBER:** 261104141

**BUSINESS ADDRESS:**
- **STREET 1:** 2020 CALAMOS COURT
- **STREET 2:** C/O CALAMOS ADVISORS LLC
- **CITY:** NAPERVILLE
- **STATE:** IL
- **ZIP:** 60563
- **BUSINESS PHONE:** 6302451046

**MAIL ADDRESS:**
- **STREET 1:** 2020 CALAMOS COURT
- **STREET 2:** C/O CALAMOS ADVISORS LLC
- **CITY:** NAPERVILLE
- **STATE:** IL
- **ZIP:** 60563

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CALAMOS INSURANCE TRUST
- **DATE OF NAME CHANGE:** 19990212

## Series and Classes Contracts Data

### Calamos U.S. Equity Autocallable VIP Fund (Series ID: S000105839)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000276633 | Class I      |  |
| C000276634 | Class II     |  |

**As filed with the U.S. Securities and Exchange Commission on June 18, 2026**

**Securities Act File No. 333-72511<br> Investment Company Act File No. 811-09237**

**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. 41** | x |

---

**and/or**

**REGISTRATION STATEMENT**

---

| | |
|:---|:---|
| ***UNDER THE INVESTMENT COMPANY ACT***<br> ***OF 1940***<br>| ¨ |
| **Amendment No. 43** | x |

---

**(Check appropriate box or boxes)**

**Calamos Advisors Trust** 

**(Exact Name of Registrant as Specified in Charter)**

**<br> 2020 Calamos Court**

**Naperville, Illinois 60563**

**Telephone Number: 630-245-7200**

**John P. Calamos, Sr.**

**Calamos Advisors LLC**

**2020 Calamos Court**

**Naperville, Illinois 60563**

**(Name and Address of Agent for Service)**

***With Copies to:***

**Paulita A. Pike and Rita Rubin<br> Ropes & Gray LLP<br> 191 North Wacker Drive, 32nd Floor<br> Chicago, Illinois 60606**

It is proposed that this filing will become effective:

¨ immediately upon filing pursuant to paragraph (b)

⌧ on June 23, 2026 pursuant to paragraph (b)

◻ 60 days after filing pursuant to paragraph (a)(1)

◻ on [ ] pursuant to paragraph (a)(1)

◻ 75 days after filing pursuant to paragraph (a)(2)

◻ on [ ] pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

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

CALAMOS ADVISORS TRUST

EXPLANATORY NOTE

The sole purpose of this filing is to delay the effectiveness of the Registrant's Post-Effective Amendment No. 39, as it relates to Calamos U.S. Equity Autocallable VIP Fund (the "Fund"), a series of the Registrant, until June 23, 2026.

The Registrant is submitting this Post-Effective Amendment No. 41 to its Registration Statement under the Securities Act and Amendment No. 43 to its Registration Statement under the Investment Company Act solely to designate June 23, 2026 as the new effective date for the Post-Effective Amendment pursuant to Rule 485(b) under the Securities Act.

CONTENTS OF POST EFFECTIVE AMENDMENT NO. 41

This Post-Effective Amendment to the Registration Statement comprises the following papers and documents:

The Facing Sheet

[Parts A, B and C of the Registrant's Post-Effective Amendment No. 39 under the Securities Act of 1933 as it relates to the Funds, filed on April 8, 2026](https://www.sec.gov/Archives/edgar/data/1079575/000110465926040845/tm2611348d1_485apos.htm), are incorporated by reference herein.

**Signatures** 

Pursuant to the requirements of the Securities Act of 1933, as amended (the "Securities Act") 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 and has duly caused this Post-Effective Amendment No. 41 to its Registration Statement on Form N-1A to be signed on its behalf by the undersigned, thereunto duly authorized, in this City of Naperville and State of Illinois, on the 18th day of June, 2026.

---

| | |
|:---|:---|
| Calamos Advisors Trust | Calamos Advisors Trust |
| By: | /s/ John P. Calamos, Sr. |
|  | John P. Calamos, Sr. |
|  | Trustee and President |

---

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed below by the following persons in the capacities and on the date indicated:

---

| | | |
|:---|:---|:---|
| **Name** | **Title** | **Date** |
| /s/ John P. Calamos, Sr. | Trustee and President | June 18, 2026 |
| John P. Calamos, Sr. | (principal executive officer) |  |
| /s/ John S. Koudounis\*\* | Trustee and Vice President | June 18, 2026 |
| John S. Koudounis |  |  |
| /s/ Hugh P. Armstrong\*\* | Trustee | June 18, 2026 |
| Hugh P. Armstrong |  |  |
| /s/ Virginia G. Breen\* | Trustee | June 18, 2026 |
| Virginia G. Breen |  |  |
| /s/ Jeffrey S. Phlegar\*\* | Trustee | June 18, 2026 |
| Jeffrey S. Phlegar |  |  |
| /s/ William Rybak\* | Trustee | June 18, 2026 |
| William Rybak |  |  |
| /s/ Karen L. Stuckey\* | Trustee | June 18, 2026 |
| Karen L. Stuckey |  |  |
| /s/ Christopher M. Toub\* | Trustee | June 18, 2026 |
| Christopher M. Toub |  |  |
| /s/ Lloyd A. Wennlund\* | Trustee | June 18, 2026 |
| Lloyd A. Wennlund |  |  |
| /s/ Thomas E. Herman | Vice President and Chief Financial Officer | June 18, 2026 |
| Thomas E. Herman | (principal accounting officer) |  |

---

\*An original power of attorney authorizing John P. Calamos, Sr. to execute this Registration Statement, and amendments thereto, for Messrs. Rybak, Toub, Wennlund, and Mses. Breen and Stuckey, each a trustee of the Registrant on whose behalf this Registration Statement is filed, was previously executed, and [previously filed](https://www.sec.gov/Archives/edgar/data/826732/000110465925017350/tm251599d1_ex99-xqx1.htm) as an exhibit.

\*\*An original power of attorney authorizing John P. Calamos, Sr. to execute this Registration Statement, and amendments thereto, for Messrs. Koudounis, Armstrong, and Phlegar, each a trustee of the Registrant on whose behalf this Registration Statement is filed, was previously executed, and [previously filed](https://www.sec.gov/Archives/edgar/data/1079575/000110465926040845/tm2611348d1_ex99-xqx2.htm) as an exhibit.

---

| | |
|:---|:---|
| By: | /s/ John P. Calamos, Sr. |
|  | John P. Calamos, Sr. |
|  | Attorney-in-Fact |
|  | June 18, 2026 |

---