[Form 4/A] A10 Networks, Inc. Amended Insider Trading Activity

Rhea-AI Filing Summary

A10 Networks, Inc. General Counsel Robert Scott Weber filed an amended insider report updating a prior tax-related share disposition. The filing corrects the price per share reported for 1,930 shares of common stock that were withheld on a non-discretionary basis to cover taxes tied to performance-based restricted stock units that vested on May 14, 2026. These RSUs were granted on February 6, 2025 and February 12, 2026. Following the withholding, Weber directly holds 65,527 shares of A10 Networks common stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Weber Robert Scott

Role General Counsel

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	1,930	$28.03	$54K

Holdings After Transaction: Common Stock — 65,527 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares withheld for taxes: 1,930 shares Withholding price per share: $28.03 per share Shares held after transaction: 65,527 shares +1 more

4 metrics

Shares withheld for taxes 1,930 shares Common stock withheld for tax liability on RSU vesting May 14, 2026

Withholding price per share $28.03 per share Corrected Column 4 price for withheld shares

Shares held after transaction 65,527 shares Direct ownership after tax-withholding disposition

Tax-withholding share count 1,930 shares Reported as taxWithholdingShares in transaction summary

Key Terms

tax-withholding disposition, performance-based restricted stock unit, Form 4/A, non-discretionary basis

4 terms

tax-withholding disposition financial

"transaction_action: "tax-withholding disposition""

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.

performance-based restricted stock unit financial

"related to a February 6, 2025 performance-based restricted stock unit grant"

A performance-based restricted stock unit is a promise of company shares given to an employee that only becomes actual stock if specific performance targets are met and any required time at the company is completed. For investors, these awards matter because they can dilute existing shares when earned and signal management’s confidence or the company’s expected future performance, much like a bonus cheque that only clears when pre-set goals are reached.

Form 4/A regulatory

"This amendment to the original Form 4 filed on May 15, 2026"

Form 4/A is an amended filing that corrects or updates an earlier Form 4, the mandatory report that insiders (like company executives, directors, or large shareholders) must file when their ownership stakes change. Think of it as an edited receipt showing who bought or sold stock and when; investors use it to track insider confidence, detect potential conflicts, and spot trading patterns that might signal future company prospects.

non-discretionary basis financial

"shares withheld, on a non-discretionaly basis, for tax purposes"

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^*

Weber Robert Scott

(Last) (First) (Middle)

C/O A10 NETWORKS, INC.

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)
	General Counsel

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/15/2026

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)
05/15/2026

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	05/15/2026		F		1,930	D	$28.03(1)	65,527	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

Explanation of Responses:

1. This amendment to the original Form 4 filed on May 15, 2026 is being filed to correct the price reported in Column 4 of Table I in connection with the shares withheld, on a non-discretionaly basis, for tax purposes related to a February 6, 2025 performance-based restricted stock unit grant and a February 12, 2026 performance-based restricted stock unti grant, each that vested on May 14, 2026.

Remarks:

	/s/ Jill Osato, Attorney-in-fact	05/15/2026
	** 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)