X0306 4 2019-02-01 0 0001048695 F5 NETWORKS INC FFIV 0001526624 Locoh-Donou Francois C/O F5 NETWORKS, INC. 401 ELLIOTT AVE. W. SEATTLE WA 98119 1 1 0 0 President, CEO & Director Common Stock 2019-02-01 4 M 0 8779 0.00 A 29639 D Common Stock 2019-02-04 4 S 0 4024 159.50 D 25615 D Common Stock 2019-02-04 4 S 0 12 160.7771 D 25603 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 1425 0.00 D Common Stock 1425 15678 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 3769 0.00 D Common Stock 3769 18848 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 491 0.00 D Common Stock 491 4416 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 1349 0.00 D Common Stock 1349 12143 D Restricted Stock Unit 0.00 2019-02-01 4 M 0 1745 0.00 D Common Stock 1745 19195 D Shares acquired upon vesting of the May 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. This transaction was executed pursuant to a Rule 10b5-1 trading plan, in multiple trades at prices ranging from $160.6302 to $160.9908. The reported price is the weighted average sale price. The reporting person undertakes to provide to the Company, any security holder of the Company, or Securities and Exchange Commission staff,upon request, complete information regarding the number of shares sold at each separate price. Each Restricted Stock Unit represents a contingent right to receive one share of F5 Networks, Inc. Common Stock on the vest date. This November 1, 2017 award of service-based Restricted Stock Units vests in sixteen equal quarterly increments beginning February 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. This May 1, 2017 award of service-based Restricted Stock Units vests thirty-three and one third percent (33 1/3%) on May 1, 2018 and the remaining sixty-six and two thirds percent (66 2/3%) vests in eight equal quarterly increments beginning August 1, 2018. This May 1, 2017 award of service-based Restricted Stock Units vests twenty five percent (25%) on May 1, 2018 and the remaining seventy five percent (75%) vests in twelve equal quarterly increments beginning August 1, 2018. This May 1, 2017 award of service-based Restricted Stock Units vests in sixteen equal quarterly increments beginning August 1, 2017. 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