X0306 4 2016-01-28 0 0001078075 NETSCOUT SYSTEMS INC NTCT 0001233501 MULLARKEY VINCENT J C/O NETSCOUT SYSTEMS, INC. 310 LITTLETON ROAD WESTFORD MA 01886 1 0 0 0 Common Stock 2016-01-28 4 S 0 16000 22.1547 D 34759 D The reporting person had no discretion with respect to the sale of these shares. This represents an involuntary sale effected by a financial institution pursuant to a margin call created when the issuer's stock traded below certain price levels. 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 $22.06 to $22.27 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 (2) to this Form 4. /s/ Greg Sloan by Power of Attorney 2016-02-01