X0306 4 2019-02-01 0 0001048695 F5 NETWORKS INC FFIV 0001746640 WHALEN CHAD MICHAEL C/O F5 NETWORKS, INC. 401 ELLIOTT AVE. WEST SEATTLE WA 98119 0 1 0 0 EVP, Worldwide Sales Common Stock 2019-02-01 4 M 0 877 0.00 A 1089 D Common Stock 2019-02-04 4 S 0 378 159.50 D 711 D Common Stock 2019-02-04 4 S 0 1 160.9717 D 710 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 213 0.00 D Common Stock 213 1701 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 83 0.00 D Common Stock 83 249 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 581 0.00 D Common Stock 581 6399 D Shares acquired upon vesting of the February 1, 2017, November 1, 2017, and November 1, 2018 awards of service-based Restricted Stock Units. This transaction was executed pursuant to a Rule 10b5-1 trading plan. Each Restricted Stock Unit represents a contingent right to receive one share of F5 Networks, Inc. Common Stock on the vest date. Twenty five percent (25%) of this February 1, 2017 award of service-based Restricted Stock Units vests on February 1, 2018, and the remaining seventy five percent (75%) vests in twelve equal quarterly increments beginning May 1, 2018 If the reporting person continues to serve as an officer of the Company on the vest date, the corresponding number of shares of Common Stock of F5 Networks, Inc. will be issued to the reporting person on the vest date. The service-based Restricted Stock Units (RSUs) outstanding under this 11/01/2017 grant vest as follows: 83 vest 2/1/2019, 83 vest 05/01/2019, 83 vest 08/01/2019, 83 vest 11/01/2019. This November 1, 2018 award of service-based Restricted Stock Units vests in twelve equal quarterly increments beginning February 1, 2019. /s/ Joseph P. McDermott by Power of Attorney 2019-02-05