Ribbon CFO exercises awards, settles tax in shares

Ribbon Communications EVP and CFO Eric S. Marmurek reported a series of equity award vesting events and related tax-withholding transactions in company stock.

Rhea-AI Filing Summary

Ribbon Communications EVP and CFO Eric S. Marmurek reported a series of equity award vesting events and related tax-withholding transactions in company stock. He exercised Restricted Share Units (RSUs) and Performance Share Units (PSUs) into common shares and had a portion of those shares withheld to cover taxes.

The filing shows exercises of stock units totaling 154,814 shares, offset by 61,005 shares withheld for tax obligations at prices around $2.63–$2.71 per share. These are compensation-related events rather than open-market purchases or sales, and reflect the vesting of awards tied to financial goals and total shareholder return performance through December 31, 2025.

Insider Trade Summary

154,814 shares exercised/converted

Exercise 15 txns

Insider Marmurek Eric S

Role EVP, Chief Financial Officer

Type	Security	Shares	Price	Value
Exercise	PSUs	23,146	$0.00	$0.00
Exercise	RSUs	26,043	$0.00	$0.00
Exercise	RSUs	31,646	$0.00	$0.00
Exercise	Common Stock	23,146	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	9,107	$2.63	$24K
Exercise	Common Stock	31,646	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	12,452	$2.63	$33K
Exercise	Common Stock	26,043	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	10,247	$2.63	$27K
Exercise	Performance Share Units (PSUs)	25,651	$0.00	$0.00
Exercise	PSUs	48,328	$0.00	$0.00
Exercise	Common Stock	48,328	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	19,107	$2.71	$52K
Exercise	Common Stock	25,651	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	10,092	$2.71	$27K

Holdings After Transaction: Performance Share Units (PSUs) — 0 contracts (Direct); PSUs — 0 contracts (Direct); RSUs — 83,727 contracts (Direct); Common Stock — 543,706 shares (Direct)

Footnotes (7)

1. F1. Each Restricted Share Unit (RSU) and Performance Share Unit (PSU) converts into common stock on a one-for-one basis.
2. F2. Reflects shares of Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of the awards.
3. F3. 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. F4. 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. F5. 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. F6. 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. F7. 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.

Key Figures

Shares from award exercises: 154,814 shares Shares withheld for taxes: 61,005 shares Tax-withholding price (May 15, 2026): $2.63 per share +3 more

6 metrics

Shares from award exercises 154,814 shares Total derivative exercises (RSUs and PSUs) reported

Shares withheld for taxes 61,005 shares Total F-code tax-withholding dispositions

Tax-withholding price (May 15, 2026) $2.63 per share Common stock withheld to satisfy tax obligations

Tax-withholding price (April 17, 2026) $2.71 per share Common stock withheld to satisfy tax obligations

RSUs converted 57,689 units RSUs converting to common stock one-for-one

PSUs converted 97,125 units PSUs converting to common stock one-for-one

Key Terms

Restricted Share Unit (RSU), Performance Share Unit (PSU), total shareholder return (TSR), Compensation Committee, +1 more

5 terms

Restricted Share Unit (RSU) financial

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

Performance Share Unit (PSU) financial

"The number of PSUs earned and issued upon vesting was determined based on goals set by the Compensation Committee."

total shareholder return (TSR) financial

"determined based on the Issuer's total shareholder return (TSR) compared to pre-established relative TSR goals"

Total shareholder return (TSR) measures how much an investment in a company's stock has grown over a specific period by combining the change in the share price and all dividends paid, expressed as a percentage. Think of it like tracking the total balance of a savings jar that increases both from added cash (dividends) and a rising sticker price on the jar (share price); investors use TSR to compare how well different stocks or managers deliver real, money-in-hand returns.

Compensation Committee financial

"goals (set by the Compensation Committee of the Issuer's Board of Directors)"

A compensation committee is a group within a company's leadership responsible for setting and reviewing how much top executives and employees are paid, including salaries, bonuses, and benefits. It matters to investors because fair and effective pay decisions can influence a company's performance, leadership motivation, and overall governance, helping ensure that the company’s management is aligned with shareholders’ interests.

tax withholding obligations financial

"shares of Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of the awards"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Ribbon Communications (RBBN) CFO Eric Marmurek report in this Form 4?

Eric Marmurek reported vesting and settlement of equity awards. He exercised RSUs and PSUs into common stock and had some shares withheld to pay taxes, reflecting routine compensation-related transactions rather than open-market buying or selling.

How many Ribbon Communications (RBBN) shares were acquired through award exercises?

The Form 4 shows exercises totaling 154,814 shares. These came from Restricted Share Units and Performance Share Units that converted into common stock on a one-for-one basis when vesting conditions tied to financial performance and total shareholder return were met.

How many Ribbon Communications (RBBN) shares were withheld for taxes?

A total of 61,005 shares were withheld for tax obligations. The issuer retained these common shares, at prices around $2.63–$2.71 per share, to satisfy withholding due upon vesting of the CFO’s equity awards.

Were Eric Marmurek’s Ribbon (RBBN) transactions open-market buys or sells?

No, the transactions were not open-market trades. They consist of derivative exercises of RSUs and PSUs into common stock and F-code dispositions, where shares were withheld by the company to cover tax liabilities tied to award vesting.

What performance conditions affected the Ribbon (RBBN) PSU vesting for the CFO?

PSU vesting depended on financial goals and total shareholder return. Footnotes state portions of PSU awards vested based on multi-year financial targets and relative TSR versus a peer index over the three fiscal years ended December 31, 2025.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/19/2026 - 08:12 AM Learn about SEC filing dates

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Marmurek Eric S

(Last) (First) (Middle)

6500 CHASE OAKS BLVD.

STE. 100

(Street)

PLANO TEXAS 75023

(City) (State) (Zip)

UNITED STATES

(Country)

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)
	EVP, Chief Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/17/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	04/17/2026		M		48,328	A	(1)	498,135	D
Common Stock	04/17/2026		F		19,107	D	$2.71(2)	479,118	D
Common Stock	04/17/2026		M		25,651	A	(1)	504,769	D
Common Stock	04/17/2026		F		10,092	D	$2.71(2)	494,677	D
Common Stock	05/15/2026		M		23,146	A	(1)	517,823	D
Common Stock	05/15/2026		F		9,107	D	$2.63(2)	508,176	D
Common Stock	05/15/2026		M		31,646	A	(1)	540,362	D
Common Stock	05/15/2026		F		12,452	D	$2.63(2)	527,910	D
Common Stock	05/15/2026		M		26,043	A	(1)	553,953	D
Common Stock	05/15/2026		F		10,247	D	$2.63(2)	543,706	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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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
Performance Share Units (PSUs)	(1)	04/17/2026		M			25,651	(3)	(3)	Common Stock	25,651	$0	0(3)	D
PSUs	(1)	04/17/2026		M			48,328	(4)	(4)	Common Stock	48,328	$0	0(4)	D
PSUs	(1)	05/15/2026		M			23,146	(5)	(5)	Common Stock	23,146	$0	0(5)	D
RSUs	(1)	05/15/2026		M			26,043	(6)	(6)	Common Stock	26,043	$0	52,082(6)	D
RSUs	(1)	05/15/2026		M			31,646	(7)	(7)	Common Stock	31,646	$0	31,645(7)	D

Explanation of Responses:

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.

	Patrick Macken, By POA for Rick Marmurek, EVP, CFO	05/19/2026
	** Signature of Reporting Person	Date
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.
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* Form 4: SEC 1474 (03-26)