X0306 4 2015-08-06 false 0001333170 NxStage Medical, Inc. NXTM 0001195852 TOWSE MATTHEW W 350 MERRIMACK STREET LAWRENCE MA 01843 false true false false SVP and Chief Financial Office Common Stock 2015-08-06 4 S false 5455 15.52 D 12947 D This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 29, 2015. This represents the weighted average price for shares sold in multiple transactions at prices ranging from $15.50 to $15.61, inclusive. Full information regarding the number of shares sold at each separate price within the range will be provided to NxStage Medical, Inc., any security holder of NxStage Medical, Inc. or the staff of the Securities and Exchange Commission, upon request. Aras Lapinskas, attorney-in-fact for Matthew W. Towse 2015-08-10