# EDGAR Filing Document

**Accession Number:** 0001738021
**File Stem:** 0001140361-26-017650
**Filing Date:** 2026-4
**Character Count:** 2207
**Document Hash:** 7e875152b78ee373736e66c38ee2fdcd
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-26-017650.hdr.sgml**: 20260429

**ACCESSION NUMBER**: 0001140361-26-017650

**CONFORMED SUBMISSION TYPE**: DEFA14A

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20260429

**DATE AS OF CHANGE**: 20260429

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Compass Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001738021
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** DEFA14A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39696
- **FILM NUMBER:** 26910653

**BUSINESS ADDRESS:**
- **STREET 1:** 80 GUEST STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02135
- **BUSINESS PHONE:** 617-500-8099

**MAIL ADDRESS:**
- **STREET 1:** 80 GUEST STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02135

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Olivia Ventures, Inc.
- **DATE OF NAME CHANGE:** 20180419

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

#### <br>

### SCHEDULE 14A

#### <br>

#### Proxy Statement Pursuant to Section 14(a) of the

#### Securities Exchange Act of 1934

#### <br>
Filed by the Registrant ☒ Filed by a party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐ **Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))**

☐ Definitive Proxy Statement

☒ Definitive Additional Materials

☐ Soliciting Material Pursuant to §240.14a-12

## Compass Therapeutics, Inc.

#### (Name of Registrant as Specified In Its Charter)

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

#### (Name of Person(s) Filing Proxy Statement, if other than the Registrant)

#### <br>
Payment of Filing Fee (Check the appropriate box):

☒ No fee required. <br> ☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11. <br> ☐ Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

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