X0306 4 2016-02-01 0 0001484504 Gigamon Inc. GIMO 0001484010 Hooper Paul 3300 OLCOTT STREET SANTA CLARA CA 95054 1 1 0 0 Chief Executive Officer Common Stock 2016-02-01 4 M 0 20951 6.09 A 131996 D Common Stock 2016-02-01 4 S 0 30000 25.8219 D 101996 D Stock Option (right to buy) 6.09 2016-02-01 4 M 0 20951 0.00 D 2022-04-05 Common Stock 20951 31402 D The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 19, 2015. The sale price for this transaction reported in column 4 of Table I represents the weighted average sale price of the shares sold, ranging from $25.39 to $26.29 per share. Upon request by the Commission staff, the Issuer or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price. The shares subject to the option shall vest in 36 equal monthly installments beginning June 11, 2013. All share numbers and per share prices disclosed in this Form 4 give effect to the Issuer's one-for-three reverse stock split completed on May 20, 2013. /s/ Paul Shinn, Attorney-in-Fact 2016-02-02