Sec Form 4 Filing - Sambandan Sachi @ Gigamon Inc. - 2017-12-27

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Sambandan Sachi 2. Issuer Name and Ticker or Trading Symbol Gigamon Inc. [ GIMO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Sr. VP Engineering (Last) (First) (Middle) C/O GIGAMON INC., 3300 OLCOTT STREET 3. Date of Earliest Transaction (MM/DD/YY) 12/27/2017 (Street) SANTA CLARA, CA95054 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 12/27/2017 U 72,008 ( 1 ) D 0 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (right to buy) $ 17.57 12/27/2017 D 91,948 ( 3 ) 05/15/2024 Common Stock 91,948 ( 3 ) 0 D Stock Option (right to buy) $ 21.44 12/27/2017 D 30,000 ( 4 ) 02/17/2022 Common Stock 30,000 ( 4 ) 0 D Performance-Based Restricted Stock Units $ 0 12/27/2017 D 18,689 ( 5 ) ( 5 ) Common Stock 18,689 ( 5 ) 0 D Performance Shares $ 0 12/27/2017 D 25,000 ( 6 ) ( 6 ) Common Stock 25,000 ( 6 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Sambandan Sachi C/O GIGAMON INC. 3300 OLCOTT STREET SANTA CLARA, CA95054 Sr. VP Engineering Signatures /s/ Paul Shinn, Attorney-in-Fact 12/27/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Certain of these securities were restricted stock units ("RSUs") that represented the Reporting Person's right to receive shares of Common Stock of the Issuer. The RSUs were cancelled pursuant to that certain Merger Agreement, dated October 26, 2017, between the Issuer, Ginsberg Holdco, Inc. and Ginsberg Merger Sub, Inc. (the "Merger Agreement"), in exchange for a cash payment of $38.50 per share. ( 2 )Disposed of pursuant to the Merger Agreement, in exchange for a cash payment of $38.50 per share. ( 3 )The option, which provided for vesting of 25% of the option on May 15, 2015 with the remaining shares vesting in thirty six equal monthly installments thereafter, was cancelled pursuant to the Merger Agreement, in exchange for a cash payment equal to the difference between $38.50 and the per share exercise price of the option. ( 4 )The option, which provided for vesting of 25% of the option on February 17, 2016 with the remaining shares vesting in thirty six equal monthly installments thereafter, was cancelled pursuant to the Merger Agreement, in exchange for a cash payment equal to the difference between $38.50 and the per share exercise price of the option. ( 5 )The performance-based RSUs, originally for 20,000 shares and reflected the target number and were to be based on the achievement of certain performance metrics for 2016 (and was later restated to reflect the achievement of approximately 150% of the performance criteria) for which the Reporting Person was eligible to receive up to 200% of the target number based on the achievement of the performance metrics and of which an aggregate of 11,211 shares have been exercised, was cancelled pursuant to the Merger Agreement, in exchange for a cash payment of $38.50 per share. ( 6 )The performance shares, which reflected the target number and were to be based on the achievement of certain performance metrics for 2017 and for which the Reporting Person was eligible to receive up to 200% of the target number based on the achievement of the performance metrics, was cancelled pursuant to the Merger Agreement for no consideration.

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 4(b)(v).

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