Sec Form 4 Filing - Marmurek Eric S @ Ribbon Communications Inc. - 2024-04-17

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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Marmurek Eric S 2. Issuer Name and Ticker or Trading Symbol Ribbon Communications Inc. [ RBBN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP, Finance & CAO (Last) (First) (Middle) 6500 CHASE OAKS BLVD., STE. 100 3. Date of Earliest Transaction (MM/DD/YY) 04/17/2024 (Street) PLANO, TX75023 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 04/17/2024 M 46,469 A 298,308 D Common Stock 04/17/2024 F 17,069 D $ 2.61 ( 2 ) 281,239 D Common Stock 04/18/2024 M 13,354 A 294,593 D Common Stock 04/18/2024 F 4,895 D $ 2.57 ( 2 ) 289,698 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Restricted Stock Units (RSUs) ( 1 ) 04/17/2024 M 46,469 ( 3 ) ( 3 ) Common Stock 46,469 $ 0 46,468 D RSUs ( 1 ) 04/18/2024 M 13,354 ( 4 ) ( 4 ) Common Stock 13,354 $ 0 26,709 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Marmurek Eric S 6500 CHASE OAKS BLVD. STE. 100 PLANO, TX75023 SVP, Finance & CAO Signatures Patrick Macken, By POA from Rick Marmurek, SVP, CAO 04/19/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each Restricted Stock Unit (RSU) 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. ( 3 )The RSUs were granted on April 17, 2023 and vested as to one-half on April 17, 2024; the remaining half of the RSUs vest in two equal installments thereafter on July 17, 2024 and October 17, 2024. ( 4 )The RSUs were granted on April 18, 2022 and vested as to one-third on April 18, 2023; the remaining two-thirds of the RSUs will vest in four equal semi-annual installments thereafter through April 18, 2025.

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.