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 OF SECURITIES 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 * PAR CAPITAL MANAGEMENT INC   2. Issuer Name and Ticker or Trading Symbol AMERISTAR CASINOS INC [ASCA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) ONE INTERNATIONAL PLACE SUITE 2401,  3. Date of Earliest Transaction (Month/Day/Year) 04/20/2011 (Street) BOSTON, MA 02110 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ 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 (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) Code V Amount (A) or (D) Price Common Stock 04/20/2011   S   49,300 D $ 19.27 3,569,510 D (1)   Common Stock 04/20/2011   S   99,972 D $ 19.29 3,469,538 D (1)   Common Stock 04/21/2011   S   25,000 D $ 19.36 3,444,538 D (1)   Common Stock 04/21/2011   S   75,000 D $ 19.44 3,369,538 D (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 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

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
PAR CAPITAL MANAGEMENT INC ONE INTERNATIONAL PLACE SUITE 2401 BOSTON, MA 02110		X
PAR INVESTMENT PARTNERS LP ONE INTERNATIONAL PLACE, SUITE 2401 BOSTON, MA 02110		X
PAR Group, L.P. ONE INTERNATIONAL PLACE SUITE 2401 BOSTON, MA 02110		X

Signatures

Steven M. Smith, Chief Operating Officer and General Counsel		04/25/2011
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	These securities are held directly by PAR Investment Partners, L.P. ("PIP"). PAR Group, L.P. ("PAR Group") is the general partner of PIP and PAR Capital Management, Inc. ("PCM") is the general partner of PAR Group. Each of PCM and PAR Group disclaims beneficial ownership of these securities except to the extent of their respective interests therein, if any, as a result of their direct or indirect ownership interests in PIP and a contingent right on the part of PAR Group to receive a performance-based incentive allocation from PIP.

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