X0609 4 2026-09-04 0 0001288847 Five9, Inc. FIVN 0002000932 Dignan Andy false C/O FIVE9, INC. 3001 BISHOP DR., STE. #350 SAN RAMON CA 94583 0 1 0 0 President 1 Common Stock 2026-09-04 4 S 0 2900 33 D 255020 D Common Stock 2026-09-04 4 S 0 4379 33.51 D 250641 D Common Stock 2026-09-04 4 S 0 3295 33.45 D 247346 D Common Stock 2026-09-08 4 S 0 2746 31.57 D 244600 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 2, 2025. The reported sales were to cover taxes upon the vesting of restricted stock units. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.35 to $33.34, inclusive. The reporting person undertakes to provide Five9, Inc., any security holder of Five9, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $33.36 to $33.75, inclusive. The reporting person undertakes to provide Five9, Inc., any security holder of Five9, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. The reported sales were to cover taxes upon the vesting of restricted stock units. The sales reported in this Form 4 were effected in accordance with Five9, Inc.s previously established sell to cover withholding policy, the Corporations Policy. The price reported in Column 4 is a weighted average price applied to the transaction by the broker under the Corporations Policy for sales to cover taxes upon vesting of restricted stock units for all individuals, including the reporting person subject to the Corporations Policy on the date such sales occurred. The reporting person undertakes to provide Five9, Inc., any security holder of Five9, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.12 to $32.01, inclusive. The reporting person undertakes to provide Five9, Inc., any security holder of Five9, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. /s/ Tiffany Meriweather, Attorney in Fact 2026-09-09