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13D Filing: VIEX Capital Advisors and A10 Networks Inc. (ATEN)

Published on March 16, 2018 at 11:36 am by Insider Monkey Staff in Hedge Funds

A10 Networks Inc. (NYSE:ATEN): Eric Singer’s VIEX Capital Advisors filed an amended 13D.

You can check out VIEX Capital Advisors’ latest holdings and filings here.

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You can access the original SEC filing by clicking here.

Ownership Summary Table

Name Sole Voting Power Shared Voting Power Sole Dispositive Power Shared Dispositive Power Aggregate Amount Owned Power Percent of Class
VIEX Opportunities Fund 1,763,575 1,763,575 2.5%
VIEX Special Opportunities Fund II 2,033,808 2,033,808 2.9%
VIEX GP 1,763,575 1,763,575 2.5%
VIEX Special Opportunities GP II 2,033,808 2,033,808 2.9%
VIEX Capital Advisors 3,797,383 3,797,383 5.4%
Eric Singer 3,797,383 3,797,383 5.4%

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Page 1 of 13 – SEC Filing

UNITED STATES

SECURITIES AND EXCHANGE
COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED
IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a)
AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 1)1

A10 Networks, Inc.

(Name
of Issuer)

Common Stock, $0.00001 par value

(Title of Class of Securities)

002121101

(CUSIP Number)

ERIC SINGER

VIEX
Capital Advisors, LLC

825 Third Avenue, 33rd Floor

New York, New York 10022

STEVE WOLOSKY, ESQ.

OLSHAN FROME WOLOSKY LLP

1325 Avenue of the Americas

New York, New York 10019

(212) 451-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices
and Communications)

March 14, 2018

(Date of Event Which Requires
Filing of This Statement)

If
the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule
13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following
box ¨.

Note:  Schedules
filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See
§ 240.13d-7 for other parties to whom copies are to be sent.

1
The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to
the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided
in a prior cover page.

The information required
on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities
Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject
to all other provisions of the Act (however, see the Notes).

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Page 2 of 13 – SEC Filing

1 NAME OF REPORTING PERSON
VIEX Opportunities Fund, LP – Series One*
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐
(b) ☐
3 SEC USE ONLY
4 SOURCE OF FUNDS
WC
5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)     ☐
6 CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
NUMBER OF 7 SOLE VOTING POWER
SHARES
BENEFICIALLY – 0 –
OWNED BY 8 SHARED VOTING POWER
EACH
REPORTING 1,763,575**
PERSON WITH 9 SOLE DISPOSITIVE POWER
– 0 –
10 SHARED DISPOSITIVE POWER
1,763,575**
11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
1,763,575**
12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES     ☐
13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
2.5%
14 TYPE OF REPORTING PERSON
PN

* This Series One is part of a series of VIEX Opportunities Fund,
LP, a series limited partnership.

** Includes 120,000 shares underlying call options currently exercisable
as further described in Item 6.

2

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Page 3 of 13 – SEC Filing

1 NAME OF REPORTING PERSON
VIEX Special Opportunities Fund II, LP
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐
(b) ☐
3 SEC USE ONLY
4 SOURCE OF FUNDS
WC
5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)     ☐
6 CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
NUMBER OF 7 SOLE VOTING POWER
SHARES
BENEFICIALLY – 0 –
OWNED BY 8 SHARED VOTING POWER
EACH
REPORTING 2,033,808*
PERSON WITH 9 SOLE DISPOSITIVE POWER
– 0 –
10 SHARED DISPOSITIVE POWER
2,033,808*
11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
2,033,808*
12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES     ☐
13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
2.9%
14 TYPE OF REPORTING PERSON
PN

* Includes 180,000 shares underlying call options currently exercisable
as further described in Item 6.

3

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Page 4 of 13 – SEC Filing

1 NAME OF REPORTING PERSON
VIEX GP, LLC
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐
(b) ☐
3 SEC USE ONLY
4 SOURCE OF FUNDS
AF
5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)     ☐
6 CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
NUMBER OF 7 SOLE VOTING POWER
SHARES
BENEFICIALLY – 0 –
OWNED BY 8 SHARED VOTING POWER
EACH
REPORTING 1,763,575*
PERSON WITH 9 SOLE DISPOSITIVE POWER
– 0 –
10 SHARED DISPOSITIVE POWER
1,763,575*
11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
1,763,575*
12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES     ☐
13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
2.5%
14 TYPE OF REPORTING PERSON
OO

* Includes 120,000 shares underlying call options currently exercisable
as further described in Item 6.

4

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Page 5 of 13 – SEC Filing

1 NAME OF REPORTING PERSON
VIEX Special Opportunities GP II, LLC
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐
(b) ☐
3 SEC USE ONLY
4 SOURCE OF FUNDS
AF
5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)     ☐
6 CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
NUMBER OF 7 SOLE VOTING POWER
SHARES
BENEFICIALLY – 0 –
OWNED BY 8 SHARED VOTING POWER
EACH
REPORTING 2,033,808*
PERSON WITH 9 SOLE DISPOSITIVE POWER
– 0 –
10 SHARED DISPOSITIVE POWER
2,033,808*
11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
2,033,808*
12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES     ☐
13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
2.9%
14 TYPE OF REPORTING PERSON
OO

* Includes 180,000 shares underlying call options currently exercisable
as further described in Item 6.

5

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Page 6 of 13 – SEC Filing

1 NAME OF REPORTING PERSON
VIEX Capital Advisors, LLC
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐
(b) ☐
3 SEC USE ONLY
4 SOURCE OF FUNDS
AF
5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)     ☐
6 CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
NUMBER OF 7 SOLE VOTING POWER
SHARES
BENEFICIALLY – 0 –
OWNED BY 8 SHARED VOTING POWER
EACH
REPORTING 3,797,383*
PERSON WITH 9 SOLE DISPOSITIVE POWER
– 0 –
10 SHARED DISPOSITIVE POWER
3,797,383*
11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
3,797,383*
12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES     ☐
13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
5.4%
14 TYPE OF REPORTING PERSON
IA

* Includes 300,000 shares underlying call options currently exercisable
as further described in Item 6.

6

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Page 7 of 13 – SEC Filing

1 NAME OF REPORTING PERSON
Eric Singer
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) ☐
(b) ☐
3 SEC USE ONLY
4 SOURCE OF FUNDS
AF
5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)     ☐
6 CITIZENSHIP OR PLACE OF ORGANIZATION
USA
NUMBER OF 7 SOLE VOTING POWER
SHARES
BENEFICIALLY – 0 –
OWNED BY 8 SHARED VOTING POWER
EACH
REPORTING 3,797,383*
PERSON WITH 9 SOLE DISPOSITIVE POWER
– 0 –
10 SHARED DISPOSITIVE POWER
3,797,383*
11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
3,797,383*
12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES     ☐
13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
5.4%
14 TYPE OF REPORTING PERSON
IN

* Includes 300,000 shares underlying call options currently exercisable
as further described in Item 6.

7

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Page 8 of 13 – SEC Filing

The following constitutes
Amendment No. 1 to the Schedule 13D filed by the undersigned (the “Amendment No. 1”). This Amendment No. 1 amends the
Schedule 13D as specifically set forth herein.

Item 3. Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended
and restated to read as follows:

The Shares purchased
by Series One were purchased with working capital (which may, at any given time, include margin loans made by brokerage firms in
the ordinary course of business) in open market purchases, except as otherwise noted, as set forth in Schedule A, which is incorporated
by reference herein. The aggregate purchase price of the 1,763,575 Shares beneficially owned by Series One is approximately $10,356,357,
including brokerage commissions. The aggregate purchase price of the 120,000 Shares underlying certain call options which are currently
exercisable and may be deemed to be beneficially owned by Series One is approximately $5,300, including brokerage commissions.

The Shares purchased
by VSO II were purchased with working capital (which may, at any given time, include margin loans made by brokerage firms in the
ordinary course of business) in open market purchases, except as otherwise noted, as set forth in Schedule A, which is incorporated
by reference herein. The aggregate purchase price of the 2,033,808 Shares beneficially owned by VSO II is approximately $11,786,483,
including brokerage commissions. The aggregate purchase price of the 180,000 Shares underlying certain call options which are currently
exercisable and may be deemed to be beneficially owned by VSO II is approximately $7,950, including brokerage commissions.

Item 4. Purpose of Transaction.
Item 4 is hereby amended to add the following:

On March 14, 2018,
the Reporting Persons and the Issuer entered into a letter agreement (the “Agreement”). Pursuant to the Agreement,
the Issuer increased the size of its Board of Directors (the “Board”) to six and appointed Tor R. Braham to the Board
to serve as a Class II director with a term expiring at the Company’s 2019 Annual Meeting of Stockholders (the “2019
Annual Meeting”). The Issuer will appoint Mr. Braham to the Audit Committee and to the Compensation Committee.

The Agreement further
provides that during the Restricted Period (as defined below) if (1) Mr. Braham ceases to serve on the Board and (2) at that time
the Reporting Persons beneficially owns Shares representing in the aggregate at least 2% of the Issuers’ then-outstanding
common stock, then the Issuer and Reporting Persons will cooperate to identify (and the Board will promptly appoint) another person
to serve as a director in place of Mr. Braham.

In addition, the Issuer
will recommend that stockholders approve, at the Issuers’ 2018 Annual Meeting of Stockholders (the “2018 Annual Meeting”),
a proposal to declassify the Board. If the proposal is approved, the Board will be declassified on a “rolling” basis
beginning with the 2018 Annual Meeting such that each director serving immediately prior to the 2018 Annual Meeting will complete
his term, in general, and each director elected or appointed at or after the 2018 Annual Meeting will serve a one-year term expiring
at the next annual meeting of stockholder. The Issuer also agreed to fix the size of the Board at five directors immediately following
the 2018 Annual Meeting and through the Restricted Period.

8

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Page 9 of 13 – SEC Filing

The terms of the Agreement
provide that the Reporting Persons are subject to customary standstill obligations until 11:59 p.m., Pacific time, on the day that
is 15 business days prior to the deadline for the submission of stockholder nominations of directors and business proposals for
the 2019 Annual Meeting (the “Restricted Period”). The Reporting Persons have also agreed to vote in a manner consistent
with the recommendation of the Board, subject to certain exceptions specified in the Agreement.

The foregoing description
of the Agreement is qualified in its entirety by reference to the full text of the Agreement, which is referenced as Exhibit 99.1
hereto and is incorporated herein by reference.

Item 5. Interest in Securities of the Issuer.

Items 5(a)-(c) are hereby amended and
restated to read as follows:

The aggregate percentage
of Shares reported owned by each Reporting Person is based upon 70,751,450 Shares outstanding, which is the total number of Shares
outstanding as of October 25, 2017 as reported in the Issuer’s Quarterly Report on Form 10-Q, filed with the Securities and
Exchange Commission on November 2, 2017.

A. Series One
(a) As of the close of business on March 15, 2018, Series One beneficially owned 1,763,575 Shares,
including 120,000 Shares underlying call options currently exercisable.

Percentage: Approximately
2.5%

(b) 1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 1,763,575
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 1,763,575
(c) The transactions in the Shares by Series One since the filing of the Schedule 13D are set forth
in Schedule A and are incorporated herein by reference.
B. VSO II
(a) As of the close of business on March 15, 2018, VSO II beneficially owned 2,033,808 Shares
including 180,000 Shares underlying call options currently exercisable.

Percentage: Approximately
2.9%

(b) 1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 2,033,808
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 2,033,808
(c) The transactions in the Shares by VSO II since the filing of the Schedule 13D are set forth in
Schedule A and are incorporated herein by reference.
C. VIEX GP
(a) VIEX GP, as the general partner of Series One, may be deemed the beneficial owner of the 1,763,575
Shares beneficially owned by Series One.

Percentage: Approximately
2.5%

9

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Page 10 of 13 – SEC Filing

(b) 1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 1,763,575
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 1,763,575
(c) VIEX GP has not entered into any transactions in the Shares since the filing of the Schedule 13D.
The transactions in the shares on behalf of Series One since the filing of the Schedule 13D are set forth in Schedule A and are
incorporated herein by reference.
D. VSO GP II
(a) VSO GP II, as the general partner of VSO II, may be deemed the beneficial owner of the 2,033,808
Shares beneficially owned by VSO II.

Percentage: Approximately
2.9%

(b) 1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 2,033,808
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 2,033,808
(c) VSO GP II has not entered into any transactions in the Shares since the filing of the Schedule
13D. The transactions in the Shares on behalf of VSO II since the filing of the Schedule 13D are set forth in Schedule A and are
incorporated herein by reference.
E. VIEX Capital
(a) VIEX Capital, as the investment manager of Series One and VSO II, may be deemed the beneficial
owner of the (i) 1,763,575 Shares beneficially owned by Series One and (ii) 2,033,808 Shares beneficially owned by VSO II.

Percentage: Approximately
5.4%

(b) 1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 3,797,383
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 3,797,383
(c) VIEX Capital has not entered into any transactions in the Shares since the filing of the Schedule
13D. The transactions in the Shares on behalf of each of Series One and VSO II since the filing of the Schedule 13D are set forth
in Schedule A and are incorporated herein by reference.
F. Eric Singer
(a) Mr. Singer, as the managing member of VIEX GP and VIEX Capital, may be deemed the beneficial owner
of the (i) 1,763,575 Shares beneficially owned by Series One and (ii) 2,033,808 Shares beneficially owned by VSO II.

Percentage: Approximately
5.4%

10

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Page 11 of 13 – SEC Filing

(b) 1. Sole power to vote or direct vote: 0
2. Shared power to vote or direct vote: 3,797,383
3. Sole power to dispose or direct the disposition: 0
4. Shared power to dispose or direct the disposition: 3,797,383
(c) Mr. Singer has not entered into any transactions in the Shares since the filing of the Schedule
13D. The transactions in the Shares on behalf of each of Series One and VSO II since the filing of the Schedule 13D are set forth
in Schedule A and are incorporated herein by reference.

The filing of this
Schedule 13D shall not be construed as an admission that the Reporting Persons are, for purposes of Section 13(d) of the Securities
Exchange Act of 1934, as amended, the beneficial owners of any of the Shares reported herein. Each Reporting Person disclaims beneficial
ownership of such Shares except to the extent of his or its pecuniary interest therein.

Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.
Item 6 is hereby amended to add the following:

On March 14, 2018,
the Reporting Persons and the Issuer entered into the Agreement as defined and described in Item 4.

Item 7. Material to be Filed as Exhibits.

Item 7 is hereby amended
to add the following exhibit:

99.1 Agreement, dated March 14, 2018, by and among the Reporting Persons and the Issuer (incorporated
by reference to Exhibit 10.1 to the Form 8-K filed by the Issuer on March 16, 2018).
11

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Page 12 of 13 – SEC Filing

SIGNATURES

After reasonable inquiry
and to the best of his knowledge and belief, the undersigned certifies that the information set forth in this statement is true,
complete and correct.

Dated: March 16, 2018

VIEX Opportunities Fund, LP – Series One
By: VIEX GP, LLC
General Partner
By: /s/ Eric Singer
Name: Eric Singer
Title: Managing Member
VIEX GP, LLC
By: /s/ Eric Singer
Name: Eric Singer
Title: Managing Member
VIEX Special Opportunities Fund II, LP
By: VIEX Special Opportunities GP II, LLC
General Partner
By: /s/ Eric Singer
Name: Eric Singer
Title: Managing Member
VIEX Special Opportunities GP II, LLC
By: /s/ Eric Singer
Name: Eric Singer
Title: Managing Member
VIEX Capital Advisors, LLC
By: /s/ Eric Singer
Name: Eric Singer
Title: Managing Member
/s/ Eric Singer
Eric Singer
12

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Page 13 of 13 – SEC Filing

SCHEDULE A

Transactions in the Shares Since
the Filing of the Schedule 13D

 

Nature of the Transaction

Securities

Purchased/(Sold)

Price Per

Share($)

Date of

Purchase / Sale

VIEX
opportunities fund, LP – Series one

 

Purchase of Common Stock 44,000 6.2487 01/31/2018

 

VIEX
special opportunities fund ii, LP

 

Purchase of Common Stock 66,000 6.2487 01/31/2018

 

 

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