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).

1. Name and Address of Reporting Person* Singer Eric (Last) (First) (Middle) C/O A10 NETWORKS, INC. 2300 ORCHARD PARKWAY (Street) SAN JOSE CA 95131 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol A10 Networks, Inc. [ ATEN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 11/01/2021
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

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, par value $0.00001								73,139	D(1)(2)
Common Stock, par value $0.00001	11/01/2021		S		346,000	D	$16.0076(3)	1,119,781	I	By Viex Opportunities Fund, LP - Series One(1)(2)(4)
Common Stock, par value $0.00001	11/02/2021		S		200,050	D	$15.3412(5)	919,731	I	By Viex Opportunities Fund, LP - Series One(1)(2)(4)
Common Stock, par value $0.00001	11/03/2021		S		274,190	D	$15.7042(6)	645,541	I	By Viex Opportunities Fund, LP - Series One(1)(2)(4)
Common Stock, par value $0.00001	11/01/2021		S		122,000	D	$16.0076(3)	360,877	I	By Viex Opportunities Fund, LP - Series Two(1)(2)(7)
Common Stock, par value $0.00001	11/02/2021		S		75,019	D	$15.3412(5)	285,858	I	By Viex Opportunities Fund, LP - Series Two(1)(2)(7)
Common Stock, par value $0.00001	11/03/2021		S		102,822	D	$15.7042(6)	183,036	I	By Viex Opportunities Fund, LP - Series Two(1)(2)(7)
Common Stock, par value $0.00001	11/01/2021		S		550,000	D	$16.0076(3)	4,705,022	I	By Viex Special Opportunities Fund II, LP(1)(2)(8)
Common Stock, par value $0.00001	11/01/2021		J		2,607,705(9)	D	$0	2,097,317	I	By Viex Special Opportunities Fund II, LP(1)(2)(8)
Common Stock, par value $0.00001	11/02/2021		S		350,087	D	$15.3412(5)	1,747,230	I	By Viex Special Opportunities Fund II, LP(1)(2)(8)
Common Stock, par value $0.00001	11/03/2021		S		479,832	D	$15.7042(6)	1,267,398	I	By Viex Special Opportunities Fund II, LP(1)(2)(8)
Common Stock, par value $0.00001	11/01/2021		J		487,416(10)	D	$0	0	I	By Viex Special Opportunities Fund III, LP(1)(2)(11)

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

1. Name and Address of Reporting Person* Singer Eric (Last) (First) (Middle) C/O A10 NETWORKS, INC. 2300 ORCHARD PARKWAY (Street) SAN JOSE CA 95131 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* VIEX Opportunities Fund, LP Series One (Last) (First) (Middle) C/O A10 NETWORKS, INC. 2300 ORCHARD PARKWAY (Street) SAN JOSE CA 95131 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Opportunities Fund, LP - Series Two (Last) (First) (Middle) C/O A10 NETWORKS, INC. 2300 ORCHARD PARKWAY (Street) SAN JOSE CA 95131 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Special Opportunities Fund II, LP (Last) (First) (Middle) C/O A10 NETWORKS, INC. 2300 ORCHARD PARKWAY (Street) SAN JOSE CA 95131 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* VIEX Special Opportunities Fund III, LP (Last) (First) (Middle) C/O A10 NETWORKS, INC. 2300 ORCHARD PARKWAY (Street) SAN JOSE CA 95131 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

Explanation of Responses:

1. This Form 4 is filed jointly by VIEX Opportunities Fund, LP - Series One ("Series One"), a series of VIEX Opportunities Fund, LP, VIEX Opportunities Fund, LP - Series Two ("Series Two"), a series of VIEX Opportunities Fund, LP, VIEX Special Opportunities Fund II, LP ("VSO II"), VIEX Special Opportunities Fund III, LP ("VSO III"), VIEX GP, LLC ("VIEX GP"), VIEX Special Opportunities GP II, LLC ("VSO GP II"), VIEX Special Opportunities GP III, LLC ("VSO GP III"), VIEX Capital Advisors, LLC ("VIEX Capital"), and Eric Singer (collectively, the "Reporting Persons").

2. Each Reporting Person disclaims beneficial ownership of the securities of the Issuer reported herein except to the extent of his or its pecuniary interest therein, and this report shall not be deemed to be an admission that any Reporting Person is the beneficial owner of such securities for purposes of Section 16 or any other purpose.

3. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.00 to $18.58 per share. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote 3.

4. Securities of the Issuer beneficially owned directly by Series One. VIEX GP, as the general partner of Series One, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series One. VIEX Capital, as the investment manager of Series One, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series One. Mr. Singer, as the managing member of each of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series One.

5. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.20 to $15.525 per share. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote 5.

6. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.40 to $16.06 per share. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote 6.

7. Securities of the Issuer beneficially owned directly by Series Two. VIEX GP, as the general partner of Series Two, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series Two. VIEX Capital, as the investment manager of Series Two, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series Two. Mr. Singer, as the managing member of each of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by Series Two.

8. Securities of the Issuer beneficially owned directly by VSO II. VSO GP II, as the general partner of VSO II, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO II. VIEX Capital, as the investment manager of VSO II, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO II. Mr. Singer, as the managing member of each of VSO GP II and VIEX Capital, may be deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO II.

9. Represents a pro-rata distribution of shares to limited partners by VSO II.

10. Represents a pro-rata distribution of shares to limited partners by VSO III.

11. Securities of the Issuer that were beneficially owned directly by VSO III. VSO GP III, as the general partner of VSO III, may have been deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO III. VIEX Capital, as the investment manager of VSO III, may have been deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO III. Mr. Singer, as the managing member of each of VSO GP III and VIEX Capital, may have been deemed the beneficial owner of the securities of the Issuer beneficially owned by VSO III.

	/s/ Eric Singer	11/03/2021
	** 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).
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