FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * Summit Partners Growth Equity Fund VIII-A, L.P.   2. Issuer Name and Ticker or Trading Symbol A10 Networks, Inc. [ATEN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 222 BERKELEY STREET, 18TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 03/26/2014 (Street) BOSTON, MA 02116 4. If Amendment, Date 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 (City) (State) (Zip) 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 03/26/2014   C   9,427,846 A (1) 9,427,846 (2) D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	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 control number.		SEC 1474 (9-02)

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 Underlying Securities (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 of Derivative Security: 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

Series D Redeemable Convertible Preferred Stock

(1)

03/26/2014

C

80,000

(1)

(3)

Common Stock

9,427,846 (2)

$ 0 (1)

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Summit Partners Growth Equity Fund VIII-A, L.P. 222 BERKELEY STREET, 18TH FLOOR BOSTON, MA 02116		X
Summit Partners Growth Equity Fund VIII-B, L.P. 222 BERKELEY STREET, 18TH FLOOR BOSTON, MA 02116		X
Summit Investors I, LLC 222 BERKELEY STREET, 18TH FLOOR BOSTON, MA 02116		X
Summit Investors I (UK), L.P. 222 BERKELEY STREET, 18TH FLOOR BOSTON, MA 02116		X

Signatures

Summit Partners Growth Equity Fund VIII-A, L.P., by Summit Partners GE VII, L.P., its GP, by Summit Partners GE VII, LLC, its GP, by Summit Partners, L.P., its GP, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph Trustey, Member		03/28/2014
**Signature of Reporting Person		Date
Summit Partners Growth Equity Fund VIII-B, L.P., by Summit Partners GE VII, L.P., its GP, by Summit Partners GE VII, LLC, its GP, by Summit Partners, L.P., its GP, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph Trustey, Member		03/28/2014
**Signature of Reporting Person		Date
Summit Investors I, LLC, by Summit Investors Management, LLC, its Manager, by Summit Partners, L.P., its Managing Member, by Summit Master Company, LLC, its general partner, by Robin W. Devereux, POA for Joseph F. Trustey, Member		03/28/2014
**Signature of Reporting Person		Date
Summit Investors I (UK), L.P., by Summit Investors Management, LLC, its General Partner, by Summit Partners, L.P., its Managing Member, by Summit Master Company, its General Partner, by Robin W. Devereux, POA for Joseph F. Trustey, Member		03/28/2014
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	In connection with the closing of A10 Networks, Inc.'s (the "Issuer") initial public offering of common stock on March 26, 2014, each share of Series D Redeemable Convertible Preferred Stock automatically converted into shares of common stock at a conversion ratio of 117.8481-to-one. Prior to the conversion, each share of Series D Redeemable Convertible Preferred Stock was convertible without payment of further consideration.
(2)	The common stock is held as follows: 6,873,136 in the name of Summit Partners Growth Equity Fund VIII-A, L.P.; 2,510,989 in the name of Summit Partners Growth Equity Fund VIII-B, L.P., 40,186 in the name of Summit Investors I, LLC; and 3,535 in the name of Summit Investors I (UK), L.P.
(3)	The Series D Redeemable Convertible Preferred Stock had no expiration date.
Remarks: The entities mentioned in Footnote 2 are collectively referred to as the "Summit Entities."  Each of the Summit Entities disclaims beneficial ownership of the shares except for those listed in Footnote 2 as held by such entity, except to the extent of each such entity's pecuniary interest therein.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.