# EDGAR Filing Document

**Accession Number:** 0001579881
**File Stem:** 0001104659-26-029218
**Filing Date:** 2026-3
**Character Count:** 2257
**Document Hash:** 836a682033bd0c1b1f2794ee5771ed99
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-029218.hdr.sgml**: 20260317

**ACCESSION NUMBER**: 0001104659-26-029218

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260317

**DATE AS OF CHANGE**: 20260317

**EFFECTIVENESS DATE**: 20260317

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Calamos ETF Trust
- **CENTRAL INDEX KEY:** 0001579881

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-191151
- **FILM NUMBER:** 26759961

**BUSINESS ADDRESS:**
- **STREET 1:** 2020 CALAMOS COURT
- **CITY:** NAPERVILLE
- **STATE:** IL
- **ZIP:** 60563
- **BUSINESS PHONE:** 630-245-8394

**MAIL ADDRESS:**
- **STREET 1:** 2020 CALAMOS COURT
- **CITY:** NAPERVILLE
- **STATE:** IL
- **ZIP:** 60563

## Series and Classes Contracts Data

### Calamos S&P 500 Structured Alt Protection ETF - November (Series ID: S000086985)

---

|  |  |
|:---|:---|
| Class Name                                               | Class ID   |
| Calamos S&P 500 Structured Alt Protection ETF - November | C000252655 |

---

## Series and Classes Contracts Data

### Calamos S&P 500 Structured Alt Protection ETF - November (Series ID: S000086985)

| Class ID   | Class Name                                               | Ticker Symbol   |
|:---|:---|:---|
| C000252655 | Calamos S&P 500 Structured Alt Protection ETF - November |  |

Rule 497(e)

File No. 333-191151

**CALAMOS ETF TRUST**

(the "Trust")

**Calamos S&P 500® Structured Alt Protection ETF® – November**

**(the "Fund")**

**Supplement dated March 17, 2026**

**to the Fund's Prospectus dated November 28, 2025, as amended**

*This supplement updates certain information contained in the Fund's prospectus and should be attached to the prospectus and retained for future reference.*

*Capitalized terms not defined herein have the same meaning as in the Fund's prospectus.*

Effective immediately, under the sub-heading "What are the investment objectives and principal strategies of the Fund?" on page 15 of the prospectus, the reference to "7.43%" in the fifth paragraph is replaced with "6.78%".

**Please retain this supplement for future reference**