X0306 4 2016-01-15 0001463172 Zendesk, Inc. ZEN 0001211433 BLACK ALAN J 1019 MARKET STREET SAN FRANCISCO CA 94103 1 SVP and CFO Common Stock 2016-01-09 5 G 0 E 12500 0 D 131278 D Common Stock 2016-01-09 5 G 0 E 12500 0 A 250300 I Alan J. Black and Linda J. Black, Trustees of Black Family Trust - 2001 U/I DTD. November 26, 2001 Common Stock 2016-01-15 4 M 0 375 A 131653 D Common Stock 2016-01-15 4 F 0 165 23.94 D 131488 D Common Stock 40000 I By Black 2013 Family Heritage Trust Common Stock 40000 I By Black 2014 Family Heritage Trust Restricted Stock Unit 2016-01-15 4 M 0 375 D 2022-02-04 Common Stock 375 13876 D Restricted stock units convert into common stock on a one-for-one basis. Represents the number of shares withheld by the Issuer in satisfaction of tax withholding obligations in connection with the vesting of the restricted stock units listed in Table II. Such withholding is mandated by an election of the Issuer made in advance and does not represent a discretionary trade by the reporting person. 1/48th of the shares issuable pursuant to the restricted stock units shall vest monthly after the vesting commencement date of February 15, 2015, subject to the Reporting Person's continuous service to the Issuer on each such date. Unvested shares are subject to acceleration upon the occurrence of certain events. /s/ John Geschke, Attorney-in-Fact for Alan J. Black 2016-01-19