Sec Form 4 Filing - Swan Winifred L @ NxStage Medical, Inc. - 2012-04-30

Insider filing report for Changes in Beneficial Ownership
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FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP
Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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1. Name and Address of Reporting Person
Swan Winifred L
2. Issuer Name and Ticker or Trading Symbol
NxStage Medical, Inc. [ NXTM]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
X __ Officer (give title below) _____ Other (specify below)
SVP and General Counsel
(Last) (First) (Middle)
C/O NXSTAGE MEDICAL, INC., 439 SOUTH UNION STREET, 5TH FLOOR
3. Date of Earliest Transaction (MM/DD/YY)
04/30/2012
(Street)
LAWRENCE, MA01843
4. If Amendment, Date Original Filed (MM/DD/YY)
6. Individual or Joint/Group Filing (Check Applicable Line)
__ X __ Form filed by One Reporting Person
_____ Form filed by More than One Reporting Person
(City) (State) (Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 04/30/2012 A 9,494 A $ 8.55 25,761 D
Common Stock 04/30/2012 S( 1 ) 9,494 D $ 17.1709 ( 2 ) 16,267 D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(MM/DD/YY)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (Right to Buy) $ 8.55 04/30/2012 M 9,494 09/15/2005( 3 ) 09/15/2012 Common Stock 9,494 $ 0 0 D
Reporting Owners
Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Swan Winifred L
C/O NXSTAGE MEDICAL, INC.
439 SOUTH UNION STREET, 5TH FLOOR
LAWRENCE, MA01843
SVP and General Counsel
Signatures
Winifred L. Swan 05/01/2012
Signature of Reporting Person Date
Explanation of Responses:
( 1 )This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2010, amended August 23, 2010, amended on December 16, 2010 and further amended on November 8, 2011.
( 2 )The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $16.94 to $17.60. The reporting person undertakes to provide to the issuer, any holder of the issuer's stock, or the SEC, upon request, full information regarding the number of shares sold at each separate price within the range described above.
( 3 )The stock option reported on this Form 4 was immediately exercisable as of the grant date for all shares of common stock that may be purchased under such stock option.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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