# EDGAR Filing Document

**Accession Number:** 0001579881
**File Stem:** 0001104659-25-094372
**Filing Date:** 2025-9
**Character Count:** 12048
**Document Hash:** 548f7a1b2764d3b21005659bf45d6b7e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-094372.hdr.sgml**: 20250929

**ACCESSION NUMBER**: 0001104659-25-094372

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250929

**DATE AS OF CHANGE**: 20250929

**EFFECTIVENESS DATE**: 20250929

**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:** 251354776

**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 Bitcoin 80 Series Structured Alt Protection ETF - January (Series ID: S000090058)

---

|  |  |
|:---|:---|
| Class Name                                                        | Class ID   |
| Calamos Bitcoin 80 Series Structured Alt Protection ETF - January | C000256935 |

---

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - April (Series ID: S000090059)

---

|  |  |
|:---|:---|
| Class Name                                                      | Class ID   |
| Calamos Bitcoin 80 Series Structured Alt Protection ETF - April | C000256936 |

---

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - July (Series ID: S000090060)

---

|  |  |
|:---|:---|
| Class Name                                                     | Class ID   |
| Calamos Bitcoin 80 Series Structured Alt Protection ETF - July | C000256937 |

---

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - October (Series ID: S000090061)

---

|  |  |
|:---|:---|
| Class Name                                                        | Class ID   |
| Calamos Bitcoin 80 Series Structured Alt Protection ETF - October | C000256938 |

---

### Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Jan/Jul (Series ID: S000090062)

---

|  |  |
|:---|:---|
| Class Name                                                   | Class ID   |
| Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Jan/Jul | C000256939 |

---

### Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Apr/Oct (Series ID: S000090063)

---

|  |  |
|:---|:---|
| Class Name                                                   | Class ID   |
| Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Apr/Oct | C000256940 |

---

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - January (Series ID: S000090064)

---

|  |  |
|:---|:---|
| Class Name                                                        | Class ID   |
| Calamos Bitcoin 90 Series Structured Alt Protection ETF - January | C000256941 |

---

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - April (Series ID: S000090065)

---

|  |  |
|:---|:---|
| Class Name                                                      | Class ID   |
| Calamos Bitcoin 90 Series Structured Alt Protection ETF - April | C000256942 |

---

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - July (Series ID: S000090066)

---

|  |  |
|:---|:---|
| Class Name                                                     | Class ID   |
| Calamos Bitcoin 90 Series Structured Alt Protection ETF - July | C000256943 |

---

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - October (Series ID: S000090067)

---

|  |  |
|:---|:---|
| Class Name                                                        | Class ID   |
| Calamos Bitcoin 90 Series Structured Alt Protection ETF - October | C000256944 |

---

### Calamos Bitcoin Structured Alt Protection ETF - January (Series ID: S000090114)

---

|  |  |
|:---|:---|
| Class Name                                              | Class ID   |
| Calamos Bitcoin Structured Alt Protection ETF - January | C000256995 |

---

### Calamos Bitcoin Structured Alt Protection ETF - April (Series ID: S000090115)

---

|  |  |
|:---|:---|
| Class Name                                            | Class ID   |
| Calamos Bitcoin Structured Alt Protection ETF - April | C000256996 |

---

### Calamos Bitcoin Structured Alt Protection ETF - July (Series ID: S000090116)

---

|  |  |
|:---|:---|
| Class Name                                           | Class ID   |
| Calamos Bitcoin Structured Alt Protection ETF - July | C000256997 |

---

### Calamos Bitcoin Structured Alt Protection ETF - October (Series ID: S000090117)

---

|  |  |
|:---|:---|
| Class Name                                              | Class ID   |
| Calamos Bitcoin Structured Alt Protection ETF - October | C000256998 |

---

## Series and Classes Contracts Data

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - January (Series ID: S000090058)

| Class ID   | Class Name                                                        | Ticker Symbol   |
|:---|:---|:---|
| C000256935 | Calamos Bitcoin 80 Series Structured Alt Protection ETF - January |  |

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - April (Series ID: S000090059)

| Class ID   | Class Name                                                      | Ticker Symbol   |
|:---|:---|:---|
| C000256936 | Calamos Bitcoin 80 Series Structured Alt Protection ETF - April |  |

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - July (Series ID: S000090060)

| Class ID   | Class Name                                                     | Ticker Symbol   |
|:---|:---|:---|
| C000256937 | Calamos Bitcoin 80 Series Structured Alt Protection ETF - July |  |

### Calamos Bitcoin 80 Series Structured Alt Protection ETF - October (Series ID: S000090061)

| Class ID   | Class Name                                                        | Ticker Symbol   |
|:---|:---|:---|
| C000256938 | Calamos Bitcoin 80 Series Structured Alt Protection ETF - October |  |

### Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Jan/Jul (Series ID: S000090062)

| Class ID   | Class Name                                                   | Ticker Symbol   |
|:---|:---|:---|
| C000256939 | Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Jan/Jul |  |

### Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Apr/Oct (Series ID: S000090063)

| Class ID   | Class Name                                                   | Ticker Symbol   |
|:---|:---|:---|
| C000256940 | Calamos Bitcoin Structured Alt Protection ETF - 6 Mo Apr/Oct |  |

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - January (Series ID: S000090064)

| Class ID   | Class Name                                                        | Ticker Symbol   |
|:---|:---|:---|
| C000256941 | Calamos Bitcoin 90 Series Structured Alt Protection ETF - January |  |

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - April (Series ID: S000090065)

| Class ID   | Class Name                                                      | Ticker Symbol   |
|:---|:---|:---|
| C000256942 | Calamos Bitcoin 90 Series Structured Alt Protection ETF - April |  |

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - July (Series ID: S000090066)

| Class ID   | Class Name                                                     | Ticker Symbol   |
|:---|:---|:---|
| C000256943 | Calamos Bitcoin 90 Series Structured Alt Protection ETF - July |  |

### Calamos Bitcoin 90 Series Structured Alt Protection ETF - October (Series ID: S000090067)

| Class ID   | Class Name                                                        | Ticker Symbol   |
|:---|:---|:---|
| C000256944 | Calamos Bitcoin 90 Series Structured Alt Protection ETF - October |  |

### Calamos Bitcoin Structured Alt Protection ETF - January (Series ID: S000090114)

| Class ID   | Class Name                                              | Ticker Symbol   |
|:---|:---|:---|
| C000256995 | Calamos Bitcoin Structured Alt Protection ETF - January |  |

### Calamos Bitcoin Structured Alt Protection ETF - April (Series ID: S000090115)

| Class ID   | Class Name                                            | Ticker Symbol   |
|:---|:---|:---|
| C000256996 | Calamos Bitcoin Structured Alt Protection ETF - April |  |

### Calamos Bitcoin Structured Alt Protection ETF - July (Series ID: S000090116)

| Class ID   | Class Name                                           | Ticker Symbol   |
|:---|:---|:---|
| C000256997 | Calamos Bitcoin Structured Alt Protection ETF - July |  |

### Calamos Bitcoin Structured Alt Protection ETF - October (Series ID: S000090117)

| Class ID   | Class Name                                              | Ticker Symbol   |
|:---|:---|:---|
| C000256998 | Calamos Bitcoin Structured Alt Protection ETF - October |  |

SUPPLEMENT DATED SEPTEMBER 29, 2025

CALAMOS ETF TRUST (the "Trust")

IMPORTANT NOTICE REGARDING CHANGE IN INVESTMENT POLICY

This notice contains important information for shareholders about matters affecting each of the funds listed below each of which is a series of the Trust (each, a "Fund" and collectively the "Funds") and each Fund's prospectuses dated as indicated below.

---

| | | |
|:---|:---|:---|
| # | Fund | Prospectus Date |
| 1 | Calamos Bitcoin Structured Alt Protection ETF — January | January 21, 2025 |
| 2 | Calamos Bitcoin 90 Series Structured Alt Protection ETF — January | February 3, 2025 |
| 3 | Calamos Bitcoin 80 Series Structured Alt Protection ETF — January | February 3, 2025 |
| 4 | Calamos Bitcoin Structured Alt Protection ETF — April | April 1, 2025 |
| 5 | Calamos Bitcoin 90 Series Structured Alt Protection ETF — April | April 1, 2025 |
| 6 | Calamos Bitcoin 80 Series Structured Alt Protection ETF — April | April 1, 2025 |
| 7 | Calamos Bitcoin Structured Alt Protection ETF — July | July 8, 2025 |
| 8 | Calamos Bitcoin 90 Series Structured Alt Protection ETF — July | July 8, 2025 |
| 9 | Calamos Bitcoin 80 Series Structured Alt Protection ETF — July | July 8, 2025 |
| 10 | Calamos Bitcoin Structured Alt Protection ETF — October | October 1, 2025 |
| 11 | Calamos Bitcoin 90 Series Structured Alt Protection ETF — October | October 1, 2025 |
| 12 | Calamos Bitcoin 80 Series Structured Alt Protection ETF — October | October 1, 2025 |
| 13 | Calamos Bitcoin Structured Alt Protection ETF — 6Mo Jan/Jul | February 3, 2025 |
| 14 | Calamos Bitcoin Structured Alt Protection ETF — 6Mo Apr/Oct | April 1, 2025 |

---

On September 24, 2025, the Trust's Board of Trustees approved, at the request of the Funds' investment adviser, Calamos Advisors LLC (the "Advisor"), certain changes to each Fund's principal investment strategies.

In order to provide greater flexibility to manage the unencumbered cash of each Fund and to invest in income-generating assets over and above U.S. Treasury securities, the Advisor seeks to add the use of offsetting sets of options (referred to as "box spreads") to each Fund's principal investment strategies. The Advisor anticipates that the Funds will use FLEX Options for this purpose. FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation (the "OCC").

In connection with these changes, the current investment policy by which each of the Funds, under normal market conditions, seeks to invest at least 80% of its net assets (plus borrowings for investment purposes, if any) in investments that provide exposure to Spot bitcoin will be revised to reflect each Fund's ability to engage in box spread trades. Pursuant to the amended policy, each Fund, under normal market conditions, will seek to invest at least 80% of its net assets in investments that provide exposure to Spot Bitcoin, and these investments may include investments in box spreads.

These changes are anticipated to be effective on or about November 28, 2025 and will be reflected in each Fund's prospectus at such time.

------