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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
 Washington, D.C. 20549
 FORM 10-K
 þ
    
    ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31,
2005
 OR
 o
    
    TRANSITION REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF
1934
For the transition period from _______________ to _______________.
 Commission file number: 333-120252
 Capital Auto Receivables, Inc.
Capital Auto Receivables Asset Trust 2005-SN1
  DELAWARE
(State or other jurisdiction of
incorporation or organization)
    
    38-3082892
20-2702435
(I.R.S. Employer
Identification No.)
 c/o General Motors Acceptance Corporation
200 Renaissance Center
P.O. Box 200 Detroit, Michigan
48265-2000
 (313) 556-5000
   Yes
o No
þ
 Yes
o No
þ
 þ o
 þ
  o o þ
 o þ




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INDEX
Capital Auto Receivables, Inc.
 Part IItem 1.
    
    Business
    
    
    2Item 1A.
    
    Risk Factors
    
    
    2Item 1B.
    
    Unresolved Staff
Comments
    
    
    2Item 2.
    
    Properties
    
    
    2Item 3.
    
    Legal Proceedings
    
    
    2Item 4.
    
    Submission of Matters to a Vote of Security Holders
    
    
    2Part IIItem 5.
    
    Market For Registrant's Common Equity and Related Stockholder Matters
    
    
    2Item 6.
    
    Selected Financial Data
    
    
    2Item 7.
    
    Managments Discussion and Analysis of Financial Condition and Results of Operations
    
    
    3Item 7A.
    
    Quantitative and Qualitative Disclosures About Market Risk
    
    
    3Item 8.
    
    Financial Statements and Supplementary Data
    
    
    3Item 9.
    
    Changes in and Disagreements with Accountants on Accounting and Financial Disclosure
    
    
    3Item 9A.
    
    Controls and Procedures
    
    
    3Item 9B.
    
    Other Information
    
    
    3Part IIIItem 10.
    
    Directors and Executive Officers of the Registrant
    
    
    3Item 11.
    
    Executive Compensation
    
    
    3Item 12.
    
    Security Ownership of Certain Beneficial Owners and Management
    
    
    3Item 13.
    
    Certain Relationships and Related Transactions
    
    
    4Item 14.
    
    Principal Accountant Fees and Services
    
    
    4PART IVItem 15.
    
    Exhibits, Financial Statement Schedules
    
    
    4Signature
    
    
    5Certification of Executive Officer Pursuant to Rule 13a-14/15d-14Aggregate Annual Servicing Report For Capital Auto Receivables Asset Trust 2005-SN1Capital Auto Receivables Asset Trust 2005-SN1 Annual Statement as to ComplianceReport of Independent Registered Public Accounting Firm dated March 13, 2006
  1




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Part I
 
 Item 1. Business
  
 Item
1A. Risk Factors
 
 Item
1B. Unresolved Staff Comments
 
 Item 2. Properties
 
 Item 3. Legal Proceedings
 
 Item 4. Submission of Matters to a Vote of Security Holders
 
 Part II
 
 Item 5.
Market For Registrants Common Equity and Related Stockholder Matters
 Class A-2a Notes
    
    
    7Class A-2b Notes
    
    
    7Class A-2c Notes
    
    
    1Class A-3a Notes
    
    
    34Class A-3b Notes
    
    
    8Class A-3c Notes
    
    
    1Class A-4 Notes
    
    
    6Class B-1 Notes
    
    
    17Class B-2 Notes
    
    
    10Class C Notes
    
    
    9Certificates
    
    
    1
  
 Item 6. Selected Financial Data
 2




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Item 7. Managements Discussion and Analysis of Financial Condition and Results of Operations
 LeaseDate of Trust
    
    ReceivablesSale and Servicing
    
    Aggregate
    
    Asset-Backed
    
    Asset-BackedTrust
    
    Agreement
    
    Amount
    
    Notes
    
    Certificates(millions)
    
    (millions)
    
    (millions)Capital
    
    April 28, 2005
    
    $1,970
    
    Class A-1
    
    $
    440
    
    
    $30Auto
    
    
    
    
    
    (Private Placement)
    
    (Private Placement)Receivables
    
    
    
    
    
    Class A-2a
    
    
    185Asset Trust
    
    
    
    
    
    Class A-2b
    
    
    3292005-SN1
    
    
    
    
    
    Class A-2c
    
    
    104(Private Placement)Class A-3a
    
    
    160Class A-3b
    
    
    315Class A-3c
    
    
    36(Private Placement)Class A-4
    
    
    221Class B-1
    
    
    10Class B-2
    
    
    70Class C
    
    
    70
  
 Item 7A. Quantitative and Qualitative Disclosures About market Risk
 
 Item 8. Financial Statements and Supplementary Data
 
 Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure
 
 Item 9A. Controls and Procedures
 
 Item 9B. Other Information
 
 Part III
 
 Item 10. Directors and Executive Officers of the Registrant
 
 Item 11. Executive Compensation
 
 Item 12. Security Ownership of Certain Beneficial Owners and Management
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Item 13. Certain Relationships and Related Transactions
 
 Item 14. Principal Accountant Fees and Services
 
 Part IV
 
 Item 15. Exhibits, Financial Statement Schedules
  (1)
    
    Financial Statements  Not Applicable.(2)
    
    Financial Statement Schedules  Not Applicable(3)
    
    Exhibits
 
    
    Annual Statement to Noteholders and Certificateholders stating aggregate
totals of information in distribution reports.
    
    Officers Certificate of Compliance pursuant to Section 4.01 of the Trust Sale
and Administration Agreement.
    
    Copy of Report of Independent Registered Public Accounting Firm dated March
13, 2006
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Signature
  Capital Auto Receivables Asset Trust 2005-SN1by: General Motors Acceptance Corporation(Administrator, not in its individual capacity butsolely as Administrator on behalf of the Trust.)Date:
March 31, 2006
    
    
    
    /s/ Jerome B. Van Orman, Jr.(Jerome B. Van Orman, Jr.Group Vice President and Chief Financial Officer,GMAC North American Operations )
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##### Table of Contents



Index of Exhibits
 Exhibit
    
    Description
    
    Method of Filing31
    
    Certification of Executive Officer Pursuant to Rule 13a-14/15d-14
    
    Filed herewith.99.1
    
    Aggregate Annual Servicing Report For Capital Auto Receivables Asset Trust 2005-SN1
    
    Filed herewith.99.2
    
    Capital Auto Receivables Asset Trust 2005-SN1 Annual Statement as to Compliance
    
    Filed herewith.99.3
    
    Report of Independent Registered Public Accounting Firm dated March 13, 2006
    
    Filed herewith.
 6