Annual Meeting of Stockholders

The 2017 annual meeting of stockholders (the “Annual Meeting”) of A10 Networks, Inc., a Delaware corporation, will be held on Wednesday, May 31, 2017 at 10:00 a.m. Pacific Time, at 3 West Plumeria Drive, San Jose, CA 95134

Electronic Proxy Voting

The Notice of Internet Availability of Proxy Materials containing instructions on how to access this proxy statement and our annual report is first being mailed on or about April 14, 2017 to all stockholders entitled to vote at the Annual Meeting. The proxy statement and our 2016 annual report can be accessed directly at the following Internet address: http://www.proxyvote.com. All you have to do is enter the control number located on your proxy card.