# EDGAR Filing Document

**Accession Number:** 0001818517
**File Stem:** 0001104659-25-077758
**Filing Date:** 2025-8
**Character Count:** 41649
**Document Hash:** a16e00f9d521692eea7cc8ab408062e5
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-077758.hdr.sgml**: 20250813

**ACCESSION NUMBER**: 0001104659-25-077758

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250813

**DATE AS OF CHANGE**: 20250813

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Vertex, Inc.
- **CENTRAL INDEX KEY:** 0001806837
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-PREPACKAGED SOFTWARE [7372]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 232081753
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-91604
- **FILM NUMBER:** 251213621

**BUSINESS ADDRESS:**
- **STREET 1:** 2301 RENAISSANCE BOULEVARD
- **CITY:** KING OF PRUSSIA
- **STATE:** PA
- **ZIP:** 19406
- **BUSINESS PHONE:** (800) 355-3500

**MAIL ADDRESS:**
- **STREET 1:** 2301 RENAISSANCE BOULEVARD
- **CITY:** KING OF PRUSSIA
- **STATE:** PA
- **ZIP:** 19406
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Radcliffe Amanda Westphal
- **CENTRAL INDEX KEY:** 0001818517

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G/A

**MAIL ADDRESS:**
- **STREET 1:** C/O VERTEX, INC.
- **STREET 2:** 2301 RENAISSANCE BLVD.
- **CITY:** KING OF PRUSSIA
- **STATE:** PA
- **ZIP:** 19406

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**(Amendment No. 6)**

**Issuer:** Vertex, Inc.

**Title of Class of Securities:** Class A Common Stock, $0.001 par value per share

**CUSIP Number:** 92538J106

**Date of Event Which Requires Filing of this Statement:** 06/30/2025

**Check the appropriate box to designate the rule pursuant to which this Schedule is filed:**

- [ ] Rule 13d-1(b)

- [ ] Rule 13d-1(c)

- [x] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>Amanda Radcliffe | Names of Reporting Persons<br>Amanda Radcliffe |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>33188884.22 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>84210.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>33188884.22 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>84210.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>33273094.22 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>33273094.22 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>20.9% | Percent of Class Represented by Amount in Row (9)<br>20.9% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 59,182 shares of Class A Common Stock held of record by Amanda Radcliffe, (ii) 838,000 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by Ms. Radcliffe, (iii) 32,291,702.223 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held by trusts of which Ms. Radcliffe is the trustee and (iv) 84,210 shares of Class A Common Stock jointly held by Amanda Radcliffe and Conrad Radcliffe.

---

| 1. | Names of Reporting Persons<br>Stefanie Thompson | Names of Reporting Persons<br>Stefanie Thompson |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>32986261.58 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>32986261.58 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>32986261.58 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>32986261.58 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>20.7% | Percent of Class Represented by Amount in Row (9)<br>20.7% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 51,357 shares of Class A Common Stock held of record by Stefanie Thompson, (ii) 838,000 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by Ms. Thompson and (iii) 32,096,904.588 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held by trusts of which Ms. Thompson is the trustee.

---

| 1. | Names of Reporting Persons<br>Jeffrey Westphal | Names of Reporting Persons<br>Jeffrey Westphal |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>1521822.23 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>1521822.23 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1521822.23 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1521822.23 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>1.0% | Percent of Class Represented by Amount in Row (9)<br>1.0% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 7,895 shares of Class A Common Stock held of record by Jeffrey Westphal, (ii) 388,000 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by Mr. Westphal and (iii) 1,125,927.237 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held by the 2009 Jeffrey R. Westphal Generation Skipping Trust, of which Mr. Westphal is the trustee.

---

| 1. | Names of Reporting Persons<br>Christopher Thompson | Names of Reporting Persons<br>Christopher Thompson |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>5629.04 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>5629.04 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>5629.04 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>5629.04 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>0.004% | Percent of Class Represented by Amount in Row (9)<br>0.004% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes 5,629.046 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by Christopher Thompson.

---

| 1. | Names of Reporting Persons<br>Benjamin Schmerin | Names of Reporting Persons<br>Benjamin Schmerin |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>4221.78 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>4221.78 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>4221.78 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>4221.78 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>0.003% | Percent of Class Represented by Amount in Row (9)<br>0.003% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 2,500 shares of Class A Common Stock held of record by Benjamin Schmerin and (ii) 1,721.784 shares of Class A Common Sock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by Benjamin Schmerin.

---

| 1. | Names of Reporting Persons<br>Conrad Radcliffe | Names of Reporting Persons<br>Conrad Radcliffe |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>2731647.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>2731647.37 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>2731647.37 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>2731647.37 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>1.7% | Percent of Class Represented by Amount in Row (9)<br>1.7% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 2,647,437.377 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Third Party Funded Special Needs Trust for Callum W. Radcliffe u/a of Amanda W. Radcliffe dated May 15, 2015, of which Conrad Radcliffe, Kailey Radcliffe and Antoinette Capik are the trustees and (ii) 84,210 shares of Class A Common Stock jointly held by Amanda Radcliffe and Conrad Radcliffe.

---

| 1. | Names of Reporting Persons<br>Kailey Radcliffe | Names of Reporting Persons<br>Kailey Radcliffe |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>2647437.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>2647437.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>2647437.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>2647437.37 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>5294874.75 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>5294874.75 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>3.3% | Percent of Class Represented by Amount in Row (9)<br>3.3% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 2,647,437.377 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Third Party Funded Special Needs Trust for Callum W. Radcliffe u/a of Amanda W. Radcliffe dated May 15, 2015, of which Conrad Radcliffe, Kailey Radcliffe and Antoinette Capik are the trustees and (ii) 2,647,437.377 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Item Second Irrevocable Trust FBO Kailey Radcliffe u/a of Amanda W. Radcliffe dated 10/05/2001, of which Kailey Radcliffe is the trustee.

---

| 1. | Names of Reporting Persons<br>Antoinette Capik | Names of Reporting Persons<br>Antoinette Capik |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>2647437.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>2647437.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>2647437.37 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>2647437.37 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>5294874.75 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>5294874.75 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>3.3% | Percent of Class Represented by Amount in Row (9)<br>3.3% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 includes (i) 2,647,437.377 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Third Party Funded Special Needs Trust for Callum W. Radcliffe u/a of Amanda W. Radcliffe dated May 15, 2015, of which Conrad Radcliffe, Kailey Radcliffe and Antoinette Capik are the trustees and (ii) 2,647,437.377 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Item Second Irrevocable Trust FBO Antoinette R. Radcliffe u/a of Amanda W. Radcliffe dated 10/05/2001, of which Antoinette R. Capik is the trustee.

---

| 1. | Names of Reporting Persons<br>Anne Marie Westphal | Names of Reporting Persons<br>Anne Marie Westphal |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>173074.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>173074.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>173074.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>173074.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>0.1% | Percent of Class Represented by Amount in Row (9)<br>0.1% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents (i) 173,073.706 shares of Class A Common Stock held of record by the Item Second Irrevocable Trust FBO Anne Marie Westphal u/a of Jeffrey R. Westphal dated 10/05/2001, of which Anne Marie Westphal is a trustee, and (ii) 0.294 shares of Class A Common Stock held of record by the 2020 Irrevocable Trust for Benefit of Nicholas A. Shuhan, of which Anne Marie Westphal's spouse is a trustee.

---

| 1. | Names of Reporting Persons<br>Kyle Westphal | Names of Reporting Persons<br>Kyle Westphal |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>1211100.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>1211100.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1211100.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1211100.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>0.8% | Percent of Class Represented by Amount in Row (9)<br>0.8% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents 1,211,100 shares of Class A Common Stock held of record by the Item Second Irrevocable Trust FBO Kyle R. Westphal u/a of Jeffrey R. Westphal dated 10/05/2001, of which Kyle Westphal is a trustee.

---

| 1. | Names of Reporting Persons<br>Jacob Westphal | Names of Reporting Persons<br>Jacob Westphal |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>745706.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>745706.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>745706.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>745706.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>0.5% | Percent of Class Represented by Amount in Row (9)<br>0.5% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents 745,706 shares of Class A Common Stock held of record by the Item Second Irrevocable Trust FBO Jacob J. Westphal u/a of Jeffrey R. Westphal dated 10/05/2001, of which Jacob Westphal is a trustee.

---

| 1. | Names of Reporting Persons<br>Melanie DeStefano | Names of Reporting Persons<br>Melanie DeStefano |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>1941750.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>1941750.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1941750.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1941750.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>1.2% | Percent of Class Represented by Amount in Row (9)<br>1.2% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents (i) 300,000 Class A Common Stock held of record by the Item Second Irrevocable Trust FBO Melanie H. Lucas u/a of Stefanie W. Lucas dated 10/05/2001, of which Melanie DeStefano is the trustee and (ii) 1,641,750 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Item Second Irrevocable Trust FBO Melanie H. Lucas u/a of Stefanie W. Lucas dated 10/05/2001.

---

| 1. | Names of Reporting Persons<br>Samantha Lucas | Names of Reporting Persons<br>Samantha Lucas |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>1969895.22 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>1969895.22 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1969895.22 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1969895.22 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>1.2% | Percent of Class Represented by Amount in Row (9)<br>1.2% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents 1,969,895.229 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Item Second Irrevocable Trust FBO Samantha W. Lucas u/a of Stefanie W. Lucas dated 10/05/2001, of which Samantha Lucas is the trustee.

---

| 1. | Names of Reporting Persons<br>Mackenzie Lucas | Names of Reporting Persons<br>Mackenzie Lucas |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>1941750.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>1941750.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1941750.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1941750.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>1.2% | Percent of Class Represented by Amount in Row (9)<br>1.2% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents (i) 600,000 shares of Class A Common Stock held of record by the Item Second Irrevocable Trust FBO Mackenzie S. Lucas u/a of Stefanie W. Lucas dated 10/05/2001, of which Mackenzie Lucas is the trustee and (ii) 1,341,750 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Item Second Irrevocable Trust FBO Mackenzie S. Lucas u/a of Stefanie W. Lucas dated 10/05/2001.

---

| 1. | Names of Reporting Persons<br>Andrea Schmerin | Names of Reporting Persons<br>Andrea Schmerin |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>1983967.84 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>1983967.84 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1983967.84 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1983967.84 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>1.2% | Percent of Class Represented by Amount in Row (9)<br>1.2% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents (i) 400,000 shares of Class A Common Stock held of record by the Item Second Irrevocable Trust FBO Andrea P. Lucas u/a of Stefanie W. Lucas dated 10/05/2001, of which Andrea Schmerin is the trustee and (ii) 1,583,967.84 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the Item Second Irrevocable Trust FBO Andrea P. Lucas u/a of Stefanie W. Lucas dated 10/05/2001.

---

| 1. | Names of Reporting Persons<br>Constance Thompson | Names of Reporting Persons<br>Constance Thompson |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [x] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>112580.91 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>112580.91 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>112580.91 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>112580.91 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>0.1% | Percent of Class Represented by Amount in Row (9)<br>0.1% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** The amount in Row 9 represents (i) 22,500 shares of Class A Common Stock held of record by the 2020 Irrevocable Trust for Benefit of Constance A. Thompson, of which Constance Thompson is the trustee and (ii) 90,080.918 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock held of record by the 2020 Irrevocable Trust for Benefit of Constance A. Thompson.

---

**Item 1(a). Name of Issuer:**
Vertex, Inc.

**Item 1(b). Address of Issuer's Principal Executive Offices:**
2301 Renaissance Boulevard, King of Prussia, PA, 19406

**Item 2(a). Name of Person Filing:**
Each of the following is hereinafter individually referred to as a "Reporting Person" and collectively as the "Reporting Persons."  This statement is filed on behalf of:

Amanda Radcliffe;
Stefanie Thompson;
Jeffrey Westphal;
Christopher Thompson;
Benjamin Schmerin;
Conrad Radcliffe;
Kailey Radcliffe;
Antoinette Capik;
Anne Marie Westphal;
Kyle Westphal;
Jacob Westphal;
Melanie DeStefano;
Samantha Lucas;
Mackenzie Lucas;
Andrea Schmerin; and
Constance Thompson.

**Item 2(b). Address of Principal Business Office:**
The business address for each of the Reporting Persons is c/o Vertex, Inc., 2301 Renaissance Boulevard, King of Prussia, PA 19406.

**Item 2(c). Citizenship:**
Each of the Reporting Persons is a citizen of the United States.

**Item 2(d). Title of Class of Securities:**
Class A Common Stock, $0.001 par value per share

**Item 2(e). CUSIP Number:**
92538J106

**Item 3. If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:**

(a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c) [ ] Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

(d) [ ] Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

(e) [ ] An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f) [ ] An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g) [ ] A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h) [ ] A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i) [ ] A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j) [ ] A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), if filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:

(k) [ ] Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

**Item 4. Ownership:**

**(a) Amount beneficially owned:**

The information contained on the cover pages to this Schedule 13G is incorporated by reference into this Item 4.
The ownership information presented below represents beneficial ownership of Class A Common Stock of the Issuer as of June 30, 2025, based upon 77,318,571 shares of Class A Common Stock outstanding as of August 1, 2025, and assumes the conversion of an aggregate 82,155,641 shares of Class B Common Stock, par value $0.001 per share of the Issuer (the "Class B Common Stock"), held by the Reporting Persons on a one-for-one basis.
Each of the Reporting Persons is a party to that certain Third Amended and Restated Stockholders' Agreement, dated as of July 28, 2020, by and among the Issuer and the Reporting Persons and associated trusts described above (the "Stockholders Agreement").

**(b) Percent of class:**

See Item 11 of each of the cover pages hereto.

**(c) Number of shares as to which the person has:**

**(i) Sole power to vote or to direct the vote:**

See Item 5 of each of the cover pages hereto.

**(ii) Shared power to vote or to direct the vote:**

See Item 6 of each of the cover pages hereto.

**(iii) Sole power to dispose or to direct the disposition of:**

See Item 7 of each of the cover pages hereto.

**(iv) Shared power to dispose or to direct the disposition of:**

See Item 8 of each of the cover pages hereto.

**Item 5. Ownership of Five Percent or Less of a Class.**

[x] If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.

**Item 6. Ownership of More than 5 Percent on Behalf of Another Person.**

Not Applicable

**Item 7. Identification and Classification of the Subsidiary**

Not Applicable

**Item 8. Identification and Classification of Members of the Group**

By virtue of the Stockholders Agreement and the obligations and rights thereunder, the Reporting Persons acknowledge and agree that they are acting as a "group" with the other Stockholders within the meaning of Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"). Based in part on information provided by the Issuer, as of the date hereof, such a "group" would be deemed to beneficially own an aggregate of  85,751,483 shares of Class A Common Stock, or 53.8% of the Class A Common Stock of the Issuer calculated pursuant to Rule 13d-3 of the Exchange Act. Each Reporting Person expressly disclaims beneficial ownership over any shares of Class A Common Stock that they may be deemed to beneficially own solely by reason of the Stockholder Agreement.

**Item 9. Notice of Dissolution of Group**

Not Applicable

**Item 10. Certification:**

—

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Amanda Radcliffe**

**Date:** 08/13/2025

**By:** /s/ Amanda Radcliffe

**Name & Title:** Amanda Radcliffe

**Stefanie Thompson**

**Date:** 08/13/2025

**By:** /s/ Stefanie Thompson

**Name & Title:** Stefanie Thompson

**Jeffrey Westphal**

**Date:** 08/13/2025

**By:** /s/ Jeffrey Westphal

**Name & Title:** Jeffrey Westphal

**Christopher Thompson**

**Date:** 08/13/2025

**By:** /s/ Christopher Thompson

**Name & Title:** Christopher Thompson

**Benjamin Schmerin**

**Date:** 08/13/2025

**By:** /s/ Benjamin Schmerin

**Name & Title:** Benjamin Schmerin

**Conrad Radcliffe**

**Date:** 08/13/2025

**By:** /s/ Conrad Radcliffe

**Name & Title:** Conrad Radcliffe

**Kailey Radcliffe**

**Date:** 08/13/2025

**By:** /s/ Kailey Radcliffe

**Name & Title:** Kailey Radcliffe

**Antoinette Capik**

**Date:** 08/13/2025

**By:** /s/ Antoinette Capik

**Name & Title:** Antoinette Capik

**Anne Marie Westphal**

**Date:** 08/13/2025

**By:** /s/ Anne Marie Westphal

**Name & Title:** Anne Marie Westphal

**Kyle Westphal**

**Date:** 08/13/2025

**By:** /s/ Kyle Westphal

**Name & Title:** Kyle Westphal

**Jacob Westphal**

**Date:** 08/13/2025

**By:** /s/ Jacob Westphal

**Name & Title:** Jacob Westphal

**Melanie DeStefano**

**Date:** 08/13/2025

**By:** /s/ Melanie DeStefano

**Name & Title:** Melanie DeStefano

**Samantha Lucas**

**Date:** 08/13/2025

**By:** /s/ Samantha Lucas

**Name & Title:** Samantha Lucas

**Mackenzie Lucas**

**Date:** 08/13/2025

**By:** /s/ Mackenzie Lucas

**Name & Title:** Mackenzie Lucas

**Andrea Schmerin**

**Date:** 08/13/2025

**By:** /s/ Andrea Schmerin

**Name & Title:** Andrea Schmerin

**Constance Thompson**

**Date:** 08/13/2025

**By:** /s/ Constance Thompson

**Name & Title:** Constance Thompson