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

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%