A10 Networks, Inc. — Director's Dealing 2021

Aug 12, 2021

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: A10 Networks, Inc. (ATEN)
CIK: 0001580808
Period of Report: 2021-08-02

Reporting Person: COCHRAN ROBERT D (EVP Legal & Corp Collaboration)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2021-08-02	Common Stock	M	11643	—	Acquired	280027	Direct
2021-08-10	Common Stock	M	20468	—	Acquired	300495	Direct
2021-08-10	Common Stock	S	1353	—	Disposed	299142	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2021-08-09	Performance-based Restricted Stock Units	$	M	11643	Disposed	2025-02-02	Common Stock (11643.0)	Direct
2021-08-10	Performance-based Restricted Stock Units	$	M	20468	Disposed	2024-07-02	Common Stock (20468.0)	Direct

Footnotes

F1: Performance-Based Restricted Stock Units were previously reported on February 4, 2021, each of which represents a contingent right to receive one share of common stock of ATEN, with vesting subject tothe achievement of specified levels of the volume weighted average closing prices of a share of ATEN common stock during any one hundred (100) day trading period between February 2, 2021 and February 2,2025. The achievement of the first milestone occurred on July 30, 2021, as certified by the compensation committee August 2, 2021, resulting in 11,643 units meeting the appropriate performance-basedconditions. However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-third (1/3) on August 9, 2021 and an additional one-third (1/3) on each of the first and secondanniversaries of July 30, 2021, subject to continued employment. These shares are reflected on Table I.

F2: Includes shares acquired by the Reporting Person pursuant to the Issuer's Employee Stock Purchase Plan.

F3: Performance-Based Restricted Stock Units were previously reported on July 7, 2020, each of which represents a contingent right to receive one share of common stock of ATEN, with vesting subject tothe achievement of specified levels of the volume weighted average closing prices of a share of ATEN common stock during any one hundred (100) day trading period between July 2, 2020 and July 2,2024. The achievement of the last milestone occurred on August 5, 2021, as certified by the compensation committee on August 10, 2021, resulting in 20,246 units meeting the appropriate performance-basedconditions. However, these shares remain subject to time-based vesting conditions and will therefore vest as to one-third (1/3) on August 16, 2021 and an additional one-third (1/3) on each of the first and secondanniversaries of August 5, 2021, subject to continued employment. These shares are reflected on Table I.

F4: Represents the number of shares automatically sold, on a non-discretionary basis, to cover tax withholding obligations in connection with the vesting of restricted stock units.