# EDGAR Filing Document

**Accession Number:** 0001708055
**File Stem:** 0001708055-26-000034
**Filing Date:** 2026-5
**Character Count:** 9414
**Document Hash:** c1538129c08786298641870b78f13d0f
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001708055-26-000034.hdr.sgml**: 20260519

**ACCESSION NUMBER**: 0001708055-26-000034

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260417

**FILED AS OF DATE**: 20260519

**DATE AS OF CHANGE**: 20260519

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Marmurek Eric S
- **CENTRAL INDEX KEY:** 0001720721

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38267
- **FILM NUMBER:** 26995940

**MAIL ADDRESS:**
- **STREET 1:** C/O 4 TECHNOLOGY PARK DRIVE
- **CITY:** WESTFORD
- **STATE:** MA
- **ZIP:** 01886
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Ribbon Communications Inc.
- **CENTRAL INDEX KEY:** 0001708055
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-COMPUTER INTEGRATED SYSTEMS DESIGN [7373]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 821669692
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 6500 CHASE OAKS BOULEVARD
- **CITY:** PLANO
- **STATE:** TX
- **ZIP:** 75023
- **BUSINESS PHONE:** 877-412-8867

**MAIL ADDRESS:**
- **STREET 1:** 6500 CHASE OAKS BOULEVARD
- **CITY:** PLANO
- **STATE:** TX
- **ZIP:** 75023

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Sonus Networks, Inc.
- **DATE OF NAME CHANGE:** 20171027

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Solstice Sapphire Investments, Inc.
- **DATE OF NAME CHANGE:** 20170531

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Marmurek Eric S<br><sub>(Last) (First) (Middle)</sub><br>6500 CHASE OAKS BLVD.<br>STE. 100<br><sub>(Street)</sub><br>PLANO, TX 75023<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-04-17 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_EVP, Chief Financial Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Ribbon Communications Inc. [ RBBN ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-04-17 |  | M |  | 48328 | A | <sup>(1)</sup> | 498135 | D |  |
| Common Stock | 2026-04-17 |  | F |  | 19107 | D | 2.71<sup>(2)</sup> | 479118 | D |  |
| Common Stock | 2026-04-17 |  | M |  | 25651 | A | <sup>(1)</sup> | 504769 | D |  |
| Common Stock | 2026-04-17 |  | F |  | 10092 | D | 2.71<sup>(2)</sup> | 494677 | D |  |
| Common Stock | 2026-05-15 |  | M |  | 23146 | A | <sup>(1)</sup> | 517823 | D |  |
| Common Stock | 2026-05-15 |  | F |  | 9107 | D | 2.63<sup>(2)</sup> | 508176 | D |  |
| Common Stock | 2026-05-15 |  | M |  | 31646 | A | <sup>(1)</sup> | 540362 | D |  |
| Common Stock | 2026-05-15 |  | F |  | 12452 | D | 2.63<sup>(2)</sup> | 527910 | D |  |
| Common Stock | 2026-05-15 |  | M |  | 26043 | A | <sup>(1)</sup> | 553953 | D |  |
| Common Stock | 2026-05-15 |  | F |  | 10247 | D | 2.63<sup>(2)</sup> | 543706 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Performance Share Units (PSUs) | <sup>(1)</sup> | 2026-04-17 |  | M |  |  | 25651 | <sup>(3)</sup> | <sup>(3)</sup> | Common Stock | 25651 | $0 | 0<sup>(3)</sup> | D |  |
| PSUs | <sup>(1)</sup> | 2026-04-17 |  | M |  |  | 48328 | <sup>(4)</sup> | <sup>(4)</sup> | Common Stock | 48328 | $0 | 0<sup>(4)</sup> | D |  |
| PSUs | <sup>(1)</sup> | 2026-05-15 |  | M |  |  | 23146 | <sup>(5)</sup> | <sup>(5)</sup> | Common Stock | 23146 | $0 | 0<sup>(5)</sup> | D |  |
| RSUs | <sup>(1)</sup> | 2026-05-15 |  | M |  |  | 26043 | <sup>(6)</sup> | <sup>(6)</sup> | Common Stock | 26043 | $0 | 52082<sup>(6)</sup> | D |  |
| RSUs | <sup>(1)</sup> | 2026-05-15 |  | M |  |  | 31646 | <sup>(7)</sup> | <sup>(7)</sup> | Common Stock | 31646 | $0 | 31645<sup>(7)</sup> | D |  |

---

### Footnotes:

(1) Each Restricted Share Unit (RSU) and Performance Share Unit (PSU) converts into common stock on a one-for-one basis.

(2) Reflects shares of Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of the awards.

(3) The number of PSUs earned and issued upon vesting was determined based on goals (set by the Compensation Committee of the Issuer's Board of Directors (the "Compensation Committee") on an annual basis) for each of the three fiscal years ended December 31, 2025. Based on the Compensation Committee's determination of achievement of these pre-established financial goals, 32%, 70% and 36% of the shares subject to the 2023, 2024 and 2025 financial periods, respectively, were earned and vested on April 17, 2026.

(4) The number of PSUs earned and issued upon vesting was determined based on the Issuer's total shareholder return (TSR) compared to pre-established relative TSR goals, based on the TSR of a peer index of companies (set by the Compensation Committee at the time of grant) over the three fiscal years ended December 31, 2025. Based on the Compensation Committee's determination of achievement of the pre-established TSR goal, 130% of the shares subject to the PSU award were earned and vested on April 17, 2026.

(5) The number of PSUs earned and issued upon vesting was determined based on goals (set by the Compensation Committee on an annual basis) for each of the two fiscal years ended December 31, 2025. Based on the Compensation Committee's determination of achievement of these pre-established financial goals, 70% and 36% of the shares subject to the 2024 and 2025 financial periods, respectively, were earned and vested on May 15, 2026.

(6) The RSUs were granted on May 15, 2025 and vested as to one-third on May 15, 2026; the remaining two-thirds of the RSUs will vest in four equal semi-annual installments thereafter through May 15, 2028.

(7) The RSUs were granted on May 15, 2025 and vested as to one-half on May 15, 2026; the remaining one-half of the RSUs will vest in two equal semi-annual installments thereafter through May 15, 2027.

**Signature:** Patrick Macken, By POA for Rick Marmurek, EVP, CFO  
**Date:** 2026-05-19

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**