CFO of A10 Networks (ATEN) exercises 16,695 performance RSUs, nets shares

Rhea-AI Filing Summary

A10 Networks, Inc. Chief Financial Officer Michelle Elizabeth Caron reported routine equity compensation activity involving performance-based restricted stock units and related tax withholding. On May 5, 2026, she exercised awards covering 16,695 performance-based RSUs, each converting into one share of A10 common stock after achieving specified stock price performance conditions certified in April 2026.

These RSUs remain subject to time-based vesting, with specified portions vesting on May 5, 2026 and on the first and second anniversaries of the April 2026 achievement dates, contingent on continued employment. On May 6, 2026, 2,994 shares of common stock were automatically withheld at $27.13 per share to cover tax obligations, a non-discretionary tax-withholding disposition rather than an open-market sale. After these transactions, Caron directly held 33,385 shares of A10 common stock.

Insights

Equity compensation and insider-transactions analyst

CFO exercised performance RSUs and had shares withheld for taxes, with no open-market trades.

The filing shows Michelle Elizabeth Caron, CFO of A10 Networks, Inc., converting 16,695 performance-based restricted stock units into common shares on May 5, 2026. These units were tied to stock price performance periods ending in September 2029 and February 2030, with performance achievement certified in April 2026.

The RSU awards now follow a time-based vesting schedule, with half vesting on May 5, 2026 and one-quarter on each of the first and second anniversaries of the April achievement dates, subject to continued employment. This is typical for performance-based equity, blending performance and service conditions.

A separate F-code transaction on May 6, 2026 reflects 2,994 shares withheld at $27.13 per share to satisfy tax liabilities, not an open-market sale. Following these events, Caron directly held 33,385 common shares. Overall, the activity represents routine compensation vesting and tax withholding rather than discretionary buying or selling, so its standalone informational value for investors is limited.

Insider Trade Summary

16,695 shares exercised/converted

Mixed 5 txns

Insider Caron Michelle Elizabeth

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	2,994	$27.13	$81K
Exercise	Performance-based Restricted Stock Units	13,706	$0.00	--
Exercise	Performance-based Restricted Stock Units	2,989	$0.00	--
Exercise	Common Stock	13,706	$0.00	--
Exercise	Common Stock	2,989	$0.00	--

Holdings After Transaction: Common Stock — 33,385 shares (Direct, null); Performance-based Restricted Stock Units — 0 shares (Direct, null)

Footnotes (1)

1. Performance-Based Restricted Stock Units were previously reported on October 2, 2025, each of which represents a contingent right to receive one share of common stock of ATEN, with vesting subject to the achievement of a specified level of the volume weighted average closing price of a share of ATEN common stock during any one hundred (100) day trading period between September 30, 2025 and September 30, 2029. The achievement date occurred on April 16, 2026, as certified by the compensation committee of ATEN, resulting in 13,706 units meeting the appropriate performance-based conditions. However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-half (1/2) on May 5, 2026 and an additional one-fourth (1/4) on each of the first and second anniversaries of April 16, 2026, subject to continued employment. These shares are reflected on Table I. Performance-Based Restricted Stock Units that were previously reported on February 13, 2026, each of which represents a contingent right to receive one share of common stock of ATEN, with vesting subject to the achievement of specified levels of the volume weighted average closing prices of a share of ATEN common stock during any one hundred (100) day trading period between February 12, 2026 and February 12, 2030. The first achievement date occurred on April 22, 2026, as certified by the compensation committee of ATEN, resulting in 2,989 units meeting the appropriate performance-based conditions. However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-half (1/2) on May 5, 2026 and an additional one-fourth (1/4) on each of the first and second anniversaries of April 22, 2026, subject to continued employment. These shares are reflected on Table I. Includes 2,458 shares and 536 shares automatically withheld, on a non-discretionary basis, for tax purposes related to a September 30, 2025 performance-based restricted stock unit grant and a February 12, 2026 performance-based restricted stock unit grant, respectively, each that vested on May 5, 2026.

Key Figures

RSUs exercised: 16,695 units Shares withheld for taxes: 2,994 shares Tax withholding price: $27.13 per share +3 more

6 metrics

RSUs exercised 16,695 units Performance-based RSUs converting into common stock on May 5, 2026

Shares withheld for taxes 2,994 shares Automatic tax withholding at $27.13 per share on May 6, 2026

Tax withholding price $27.13 per share Price used for 2,994-share tax-withholding disposition

Shares held after transactions 33,385 shares Direct A10 Networks common stock ownership following reported activity

Performance period window 1 Sept 30, 2025–Sept 30, 2029 Price-based performance window for 13,706 performance RSUs

Performance period window 2 Feb 12, 2026–Feb 12, 2030 Price-based performance window for 2,989 performance RSUs

Key Terms

Performance-Based Restricted Stock Units, volume weighted average closing price, time-based vesting conditions, continued employment, +1 more

5 terms

Performance-Based Restricted Stock Units financial

"Performance-Based Restricted Stock Units were previously reported on October 2, 2025, each of which represents a contingent right to receive one share of common stock"

Performance-based restricted stock units are a type of employee equity award that converts into company shares only if predefined financial or operational targets are met over a set period. Think of it like a bonus check that becomes stock only when specific goals are hit; it ties pay to results, aligning managers’ incentives with shareholders. Investors care because these awards affect future share count, executive incentives, and signal how management’s success will be measured and rewarded.

volume weighted average closing price financial

"with vesting subject to the achievement of a specified level of the volume weighted average closing price of a share of ATEN common stock"

The volume weighted average closing price is the average of a security’s closing prices over a given period where each day’s closing price is weighted by the number of shares traded that day. It gives more influence to prices on days with heavier trading, so it reflects where most market activity actually occurred rather than treating every day equally. Investors use it as a more realistic benchmark for value, performance tracking, and to compare execution quality.

time-based vesting conditions financial

"However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-half"

continued employment financial

"and an additional one-fourth on each of the first and second anniversaries of April 16, 2026, subject to continued employment"

Continued employment means that an individual remains in their current job without interruption. For investors, it signals stability and ongoing work that can affect company performance and future prospects. Like a steady heartbeat for a business, sustained employment helps ensure consistent operations and financial health.

tax-withholding disposition financial

"Includes 2,458 shares and 536 shares automatically withheld, on a non-discretionary basis, for tax purposes"

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

Form 4 Insider Transactions: What Each Field Means →

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^*

Caron Michelle Elizabeth

(Last) (First) (Middle)

2300 ORCHARD PARKWAY

(Street)

SAN JOSE CALIFORNIA 95131

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
A10 Networks, Inc. [ ATEN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/05/2026

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	05/05/2026		M		13,706(1)	A	$0	33,390	D
Common Stock	05/05/2026		M		2,989(2)	A	$0	36,379	D
Common Stock	05/06/2026		F		2,994(3)	D	$27.13	33,385	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-based Restricted Stock Units	(1)	05/05/2026		M			13,706	(1)	09/30/2029	Common Stock	13,706	$0	0	D
Performance-based Restricted Stock Units	(2)	05/05/2026		M			2,989	(2)	02/12/2030	Common Stock	2,989	$0	2,989	D

Explanation of Responses:

1. Performance-Based Restricted Stock Units were previously reported on October 2, 2025, each of which represents a contingent right to receive one share of common stock of ATEN, with vesting subject to the achievement of a specified level of the volume weighted average closing price of a share of ATEN common stock during any one hundred (100) day trading period between September 30, 2025 and September 30, 2029. The achievement date occurred on April 16, 2026, as certified by the compensation committee of ATEN, resulting in 13,706 units meeting the appropriate performance-based conditions. However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-half (1/2) on May 5, 2026 and an additional one-fourth (1/4) on each of the first and second anniversaries of April 16, 2026, subject to continued employment. These shares are reflected on Table I.

2. Performance-Based Restricted Stock Units that were previously reported on February 13, 2026, each of which represents a contingent right to receive one share of common stock of ATEN, with vesting subject to the achievement of specified levels of the volume weighted average closing prices of a share of ATEN common stock during any one hundred (100) day trading period between February 12, 2026 and February 12, 2030. The first achievement date occurred on April 22, 2026, as certified by the compensation committee of ATEN, resulting in 2,989 units meeting the appropriate performance-based conditions. However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-half (1/2) on May 5, 2026 and an additional one-fourth (1/4) on each of the first and second anniversaries of April 22, 2026, subject to continued employment. These shares are reflected on Table I.

3. Includes 2,458 shares and 536 shares automatically withheld, on a non-discretionary basis, for tax purposes related to a September 30, 2025 performance-based restricted stock unit grant and a February 12, 2026 performance-based restricted stock unit grant, respectively, each that vested on May 5, 2026.

Remarks:

	/s/ Jill Osato, as Attorney-in-Fact	05/06/2026
	** 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)

FAQ

What insider transactions did A10 Networks (ATEN) CFO Michelle Caron report?

She reported routine equity compensation activity, exercising 16,695 performance-based restricted stock units into A10 Networks common stock. These awards had met stock price performance conditions and now follow a time-based vesting schedule tied to specific 2026 achievement dates and future anniversaries.

How many A10 Networks (ATEN) shares were withheld for Michelle Caron’s taxes?

A total of 2,994 A10 Networks common shares were automatically withheld on a non-discretionary basis to cover tax obligations. The withholding occurred at a price of $27.13 per share and relates to performance-based RSUs that vested on May 5, 2026.

Did the A10 Networks (ATEN) CFO sell shares on the open market in this Form 4?

No open-market sales were reported. The only disposition was 2,994 shares withheld for taxes, categorized as a tax-withholding disposition. This reflects shares delivered back to the issuer for tax liabilities, not a discretionary sale into the market.

How many A10 Networks (ATEN) shares does CFO Michelle Caron hold after these transactions?

Following the reported transactions, Michelle Caron directly holds 33,385 shares of A10 Networks common stock. This figure reflects her position after exercising performance-based restricted stock units and the separate non-discretionary tax-withholding share disposition.

What performance conditions applied to Michelle Caron’s A10 Networks (ATEN) performance-based RSUs?

The RSUs depended on achieving specified volume weighted average closing prices over any 100-day trading period. One grant referenced a window between September 30, 2025 and September 30, 2029, and another between February 12, 2026 and February 12, 2030, with achievement certified in April 2026.

What is the vesting schedule for the A10 Networks (ATEN) performance-based RSUs in this filing?

After meeting performance targets, the RSUs vest over time: one-half of each grant vests on May 5, 2026, and an additional one-fourth on each of the first and second anniversaries of the April 2026 achievement dates, assuming Michelle Caron’s continued employment.