SEC FORM 4

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Swan Winifred L

(Last)

(First)

(Middle)

C/O NXSTAGE MEDICAL, INC.

439 SOUTH UNION STREET, 5TH FLOOR

(Street)

LAWRENCE

01843

(City)

(State)

(Zip)

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

3. Date of Earliest Transaction (Month/Day/Year)
12/30/2011

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	12/30/2011		M		11,982⁽¹⁾	A	$0.00	40,499	D
Common Stock	12/30/2011		F⁽²⁾		14,319	D	$17.78	26,180	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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Stock Unit	⁽³⁾	12/30/2011		M			11,982	⁽⁴⁾	⁽⁴⁾	Common Stock	11,982	$0.00	11,981	D

Explanation of Responses:

1. Shares of common stock acquired upon the vesting of restricted stock units.

2. This transaction reflects the withholding of shares of the Company's common stock to satisfy the reporting person's tax liability incurred in connection with the final tranche of awards granted to the reporting person on March 3, 2010 pursuant to the Company's 2009 Performance Share Plan, and the vesting of the second tranche of awards granted to the reporting person on March 8, 2011 pursuant to the Company's 2010 Performance Share Plan.

3. Each restricted stock unit represents a contingent right to receive one share of the Company's common stock

4. In March 2010, the Compensation Committee established the Company's 2010 Performance Share Plan with the amount of awards to be determined based upon the satisfaction of 2010 revenue and cash consumption targets. On March 8, 2011, the Compensation Committee granted the reporting person 35,945 restricted stock units based on its evaluation of the achievement of performance criteria under the Company's 2010 Performance Share Plan. The award vested 33 1/3rd% on the date of grant (March 8, 2011), with the balance vesting in two equal installments on December 31, 2011 and December 31, 2012.

Remarks:

	Winifred L. Swan	01/04/2012
	** Signature of Reporting Person	Date
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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.