Ribbon Communications (RBBN) COO exercises RSUs/PSUs; shares withheld to cover taxes

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Ribbon Communications EVP and COO Sam Bucci reported routine equity compensation activity involving RSUs and PSUs, not open-market trading. On April 17 and May 15, 2026, he exercised derivative awards into a total of 323,770 shares of common stock. In connection with these vestings, 173,310 shares were withheld at prices of $2.63 and $2.71 per share to cover tax obligations, as is common for stock-based compensation. Footnotes explain that the vested performance units were earned based on pre-set financial and total shareholder return goals determined by the board’s compensation committee.

Insider Trade Summary

323,770 shares exercised/converted

Mixed 18 txns

Insider Bucci Sam

Role EVP, Chief Operating Officer

Type	Security	Shares	Price	Value
Exercise	PSUs	38,578	$0.00	--
Exercise	RSUs	52,743	$0.00	--
Exercise	RSUs	83,335	$0.00	--
Exercise	Common Stock	38,578	$0.00	--
Tax Withholding	Common Stock	20,650	$2.63	$54K
Exercise	Common Stock	52,743	$0.00	--
Tax Withholding	Common Stock	28,233	$2.63	$74K
Exercise	Common Stock	83,335	$0.00	--
Tax Withholding	Common Stock	44,609	$2.63	$117K
Exercise	Restricted Share Units (RSUs)	25,815	$0.00	--
Exercise	Performance Share Units (PSUs)	42,753	$0.00	--
Exercise	PSUs	80,546	$0.00	--
Exercise	Common Stock	25,815	$0.00	--
Tax Withholding	Common Stock	13,818	$2.71	$37K
Exercise	Common Stock	42,753	$0.00	--
Tax Withholding	Common Stock	22,884	$2.71	$62K
Exercise	Common Stock	80,546	$0.00	--
Tax Withholding	Common Stock	43,116	$2.71	$117K

Holdings After Transaction: PSUs — 0 shares (Direct, null); RSUs — 52,742 shares (Direct, null); Common Stock — 556,685 shares (Direct, null); Restricted Share Units (RSUs) — 0 shares (Direct, null); Performance Share Units (PSUs) — 0 shares (Direct, null)

Footnotes (1)

Each Restricted Share Unit (RSU) and Performance Share Unit (PSU) converts into common stock on a one-for-one basis. Reflects shares of Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of the awards. The RSUs were granted on April 17, 2023 and are fully vested. 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. 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. 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. 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. 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.

Key Figures

Derivative shares exercised: 323,770 shares Shares withheld for taxes: 173,310 shares Tax withholding price (May 15, 2026): $2.63 per share +3 more

6 metrics

Derivative shares exercised 323,770 shares Total shares from RSU and PSU exercises reported

Shares withheld for taxes 173,310 shares Total common shares withheld to satisfy tax obligations

Tax withholding price (May 15, 2026) $2.63 per share Price used for several tax-withholding dispositions

Tax withholding price (April 17, 2026) $2.71 per share Price used for several tax-withholding dispositions

Exercise transactions 6 exercises Number of derivative exercise transactions (M code)

Tax-withholding transactions 6 dispositions Number of tax-withholding dispositions (F code)

Key Terms

Restricted Share Unit (RSU), Performance Share Unit (PSU), total shareholder return (TSR), tax withholding obligations

4 terms

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.

tax withholding obligations financial

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

Form 4 Insider Transactions: What Each Field Means →

05/19/2026 - 08:12 AM

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^*

Bucci Sam

(Last)

(First)

(Middle)

6500 CHASE OAKS BLVD.

SUITE 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 Operating 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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	04/17/2026		M		25,815	A	⁽¹⁾	474,626	D
Common Stock	04/17/2026		F		13,818	D	$2.71⁽²⁾	460,808	D
Common Stock	04/17/2026		M		42,753	A	⁽¹⁾	503,561	D
Common Stock	04/17/2026		F		22,884	D	$2.71⁽²⁾	480,677	D
Common Stock	04/17/2026		M		80,546	A	⁽¹⁾	561,223	D
Common Stock	04/17/2026		F		43,116	D	$2.71⁽²⁾	518,107	D
Common Stock	05/15/2026		M		38,578	A	⁽¹⁾	556,685	D
Common Stock	05/15/2026		F		20,650	D	$2.63⁽²⁾	536,035	D
Common Stock	05/15/2026		M		52,743	A	⁽¹⁾	588,778	D
Common Stock	05/15/2026		F		28,233	D	$2.63⁽²⁾	560,545	D
Common Stock	05/15/2026		M		83,335	A	⁽¹⁾	643,880	D
Common Stock	05/15/2026		F		44,609	D	$2.63⁽²⁾	599,271	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Share Units (RSUs)	⁽¹⁾	04/17/2026		M			25,815	⁽³⁾	⁽³⁾	Common Stock	25,815	$0	0⁽³⁾	D
Performance Share Units (PSUs)	⁽¹⁾	04/17/2026		M			42,753	⁽⁴⁾	⁽⁴⁾	Common Stock	42,753	$0	0⁽⁴⁾	D
PSUs	⁽¹⁾	04/17/2026		M			80,546	⁽⁵⁾	⁽⁵⁾	Common Stock	80,546	$0	0⁽⁵⁾	D
PSUs	⁽¹⁾	05/15/2026		M			38,578	⁽⁶⁾	⁽⁶⁾	Common Stock	38,578	$0	0⁽⁶⁾	D
RSUs	⁽¹⁾	05/15/2026		M			52,743	⁽⁷⁾	⁽⁷⁾	Common Stock	52,743	$0	52,742⁽⁷⁾	D
RSUs	⁽¹⁾	05/15/2026		M			83,335	⁽⁸⁾	⁽⁸⁾	Common Stock	83,335	$0	166,665⁽⁸⁾	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 RSUs were granted on April 17, 2023 and are fully vested.

4. 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.

5. 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.

6. 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.

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.

8. 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.

	Patrick Macken, By POA from Sam Bucci, EVP, Chief Operating Offcer	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.
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.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What did Ribbon Communications (RBBN) executive Sam Bucci report in this Form 4?

Sam Bucci reported routine equity compensation activity. He exercised RSUs and PSUs into common stock and had shares withheld to pay taxes, with no open-market purchases or sales disclosed in this Form 4.

How many Ribbon Communications shares did Sam Bucci acquire through option and unit exercises?

Sam Bucci exercised derivative awards covering 323,770 shares of Ribbon Communications common stock. These shares came from vested restricted share units (RSUs) and performance share units (PSUs) that convert to common stock on a one-for-one basis.

How many Ribbon Communications shares were withheld for Sam Bucci’s tax obligations?

A total of 173,310 Ribbon Communications shares were withheld to satisfy tax obligations. The withholding occurred at per-share prices of $2.63 and $2.71 in connection with the vesting of RSU and PSU awards.

Were Sam Bucci’s Ribbon Communications transactions open-market buys or sells?

The reported transactions were not open-market buys or sells. They were exercises of RSUs and PSUs and related tax-withholding dispositions, where shares were delivered back to the issuer to cover withholding taxes on vested awards.

What performance measures affected Sam Bucci’s PSU vesting at Ribbon Communications?

The PSU vesting depended on financial goals and total shareholder return (TSR). The compensation committee set annual financial targets and relative TSR goals versus a peer index, and actual vesting percentages were based on achievement over fiscal years ending December 31, 2025.

How were Ribbon Communications RSUs and PSUs converted in Sam Bucci’s Form 4?

Each RSU and PSU converted into one share of Ribbon Communications common stock. The Form 4 footnotes state that these equity awards have a one-for-one conversion ratio when they vest and are settled in common shares.