X0609 4 2026-06-06 0001078075 NETSCOUT SYSTEMS INC NTCT 0001232878 DOWNING JOHN false C/O NETSCOUT SYSTEMS, INC. 310 LITTLETON ROAD WESTFORD MA 01886 1 EVP, World-Wide Sales 1 Common Stock 2026-06-06 4 M 0 5400 A 138706 D Common Stock 2026-06-06 4 F 0 1585 40.59 D 137121 D Common Stock 2026-06-08 4 S 0 8000 40.29 D 129121 D Restricted Stock Unit 2026-06-06 4 M 0 5400 D Common Stock 5400 66150 D The shares of Common Stock were acquired upon the vesting of certain restricted stock units previously granted to the reporting person. Price is N/A. The shares of Common Stock were withheld to satisfy the reporting person's tax withholding obligation upon the vesting of restricted stock units. Represents the closing price of the Company's Common Stock on June 5, 2026. The shares of Common Stock were sold pursuant to a 10b5-1 plan adopted by the Reporting Person on November 11, 2025. The shares sold on this date were sold in multiple transactions. This price is the weighted average sales price per share; the actual sales price per share ranged from $40.01 to $40.36. The reporting person undertakes to provide to NetScout Systems, Inc., any security holder of NetScout Systems, 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 range set forth in this footnote. June 6, 2026 Date is N/A. /s/ Jeff Levinson by Power of Attorney 2026-06-09