X0306 4 2018-02-11 0 0001262039 FORTINET INC FTNT 0001418649 Jensen Keith C/O FORTINET, INC. 899 KIFER ROAD SUNNYVALE CA 94086 0 1 0 0 Chief Accounting Officer Common Stock 2018-02-11 4 M 0 357 0 A 6040 D Common Stock 2018-02-11 4 F 0 124 46.54 D 5916 D Restricted Stock Units 0 2018-02-11 4 M 0 357 0 D Common Stock 357 0 D Vesting of performance stock units earned by the Reporting Person on February 11, 2016. Exempt transaction pursuant to Section 16b-3(e) - payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3. All of the shares reported as disposed of on this line were relinquished by the Reporting Person and cancelled by the Issuer in exchange for the Issuer's agreement to pay federal and state tax withholding obligations of the Reporting Person resulting from the vesting of restricted stock units ("RSUs") . The Reporting Person did not sell or otherwise dispose of any of the shares reported on this Form 4 for any reason other than to cover required taxes. The price per share was based on the fair market value of the Issuer's common stock on the vesting and release date, which, because such date was a Sunday, was the NASDAQ closing price on the last trading date immediately preceding the vesting and release date. Each RSU represents a contingent right to receive one share of the Issuer's common stock. 357 shares vested on February 11,2016. 50% of the remaining RSUs vested on February 11, 2017 and 50% vested on February 11, 2018. Shares of the Issuer's common stock will be delivered to the Reporting Person upon vesting. /s/ John Whittle, by power of attorney 2018-02-12