SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

DiMarino Dino

(Last)

(First)

(Middle)

C/O MIMECAST NORTH AMERICA, INC.

191 SPRING STREET

(Street)

LEXINGTON

02421

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
10/01/2019

3. Issuer Name and Ticker or Trading Symbol
Mimecast Ltd [ MIME ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Chief Revenue Officer

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Ordinary Shares	1,323	D
Restricted Share Units⁽¹⁾	5,625⁽²⁾	D
Restricted Share Units⁽¹⁾	15,000⁽³⁾	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Share Option (Right to Buy)	⁽⁴⁾	09/01/2026	Ordinary Shares	78,125⁽⁴⁾	$16.64	D
Share Option (Right to Buy)	⁽⁵⁾	04/02/2028	Ordinary Shares	35,000⁽⁵⁾	$34.82	D
Share Option (Right to Buy)	⁽⁶⁾	04/01/2029	Ordinary Shares	30,000⁽⁶⁾	$47.23	D

Explanation of Responses:

1. Each restricted share unit represents a contingent right to receive one share of the Issuer's ordinary shares.

2. These restricted share units (7,500) were granted on April 2, 2018. Twenty-five percent (25%) of the units vested 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 each such vesting date.

3. These restricted share units were granted on April 1, 2019. Twenty-five percent (25%) of the units vest on April 1, 2020 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 each such vesting date.

4. Represents shares underlying unexercised share options that were granted on September 1, 2016. The terms of the original grant of 250,000 options provide that twenty-five percent (25%) of the shares vested on September 1, 2017 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 each such vesting date.

5. This option was granted on April 2, 2018. Twenty-five percent (25%) of the shares vested on April 1, 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 each such vesting date.

6. This option was granted on April 1, 2019. Twenty-five percent (25%) of the shares vest on April 1, 2020, 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 each such vesting date.

Remarks:

Exhibit 24 Power of Attorney (filed herewith).

	/s/ Robert P. Nault, Attorney-in-Fact	10/01/2019
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.