X0306 4 2018-04-02 0 0001644675 Mimecast Ltd MIME 0001734756 Campbell Peter Andrew James C/O MIMECAST NORTH AMERICA, INC. 191 SPRING STREET LEXINGTON MA 02421 0 1 0 0 Chief Financial Officer Restricted Share Units 2018-04-02 4 A 0 8000 0.00 A 8000 D Ordinary Shares 248516 D Ordinary Shares 4571 I By Spouse Share Option (Right to Buy) 34.82 2018-04-02 4 A 0 41000 0.00 A 2028-04-02 Ordinary Shares 41000 41000 D Each restricted share unit represents the contingent right to receive one share of the Issuer's ordinary shares. These restricted share units were granted on April 2, 2018. Twenty-five percent (25%) of the units vest on April 2, 2019 and the remainder of the units vest on an annual basis over the next three (3) years, provided that the Reporting Person remains an employee of the Issuer on such vesting date. This option was granted on April 2, 2018. Twenty-five percent (25%) of the shares vest on April 2, 2019 and the remainder of the shares vest on a quarterly basis over the next three (3) years, provided that the Reporting Person remains an employee of the Issuer on such vesting date. Exhibit 24 Power of Attorney (incorporated by reference to Power of Attorney filed as Exhibit 24 to Form 3 filed by the Reporting Person on April 2, 2018) /s/ Lauren Schwarzenholzer, Attorney-in-Fact 2018-04-04