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UNITED STATES SECURITIES AND EXCHANGE COMMISSION
 WASHINGTON, D.C. 20549
 FORM 11-K
  þ
    
    ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934.
 For the Fiscal Year Ended December 31, 2010
 OR
 o
    
    TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934.
 For the transition period from  to
 Commission file number 1-16455
 A.
    
    Full title of the plan and the address of the plan, if different from that of the issuer
named below:
 GenOn Energy Union Savings Plan
   B.
    
    Name and issuer of the securities held pursuant to the plan and the address of its principal
executive office:




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GENON ENERGY UNION SAVINGS PLAN
 TABLE OF CONTENTS
 REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
    
    
    1FINANCIAL STATEMENTS:Statements of Net Assets Available for Benefits as of December 31, 2010 and 2009
    
    
    2Statement of Changes in Net Assets Available for Benefits for the Year Ended
December 31, 2010
    
    
    3Notes to Financial Statements
    
    
    4SUPPLEMENTAL SCHEDULE:Schedule H, line 4(i)  Schedule of Assets (Held at End of Year) as of December 31, 2010
    
    
    13EXHIBIT:Consent of Independent Registered Public Accounting Firm  Melton & Melton, L.L.P. (Exhibit 23.1)Exhibit 23.1




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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
       
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GENON ENERGY UNION SAVINGS PLAN
 
 STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS  AS OF DECEMBER 31, 2010 AND 2009
 December 31,2010
    
    
    2009ASSETS:Investments, at fair value
    
    $
    154,749,639
    
    
    $
    104,455,884Receivables:Contributions Receivable-Employer
    
    
    908,123
    
    
    
    190,944Contributions Receivable-Participants
    
    
    6,752
    
    
    
    Notes Receivable from Participants
    
    
    3,218,439
    
    
    
    2,300,379Assets Receivable from Merged Plan
    
    
    41,365,985
    
    
    
    Total Receivables
    
    
    45,499,299
    
    
    
    2,491,323NET ASSETS AVAILABLE FOR BENEFITS AT FAIR VALUE
    
    
    200,248,938
    
    
    
    106,947,207Adjustment from fair value to contract
value for fully benefit-responsive
investment contracts
    
    
    (2,030,034
    )
    
    
    (409,469
    )NET ASSETS AVAILABLE FOR BENEFITS
    
    $
    198,218,904
    
    
    $
    106,537,738
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GENON ENERGY UNION SAVINGS PLAN
 
 STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS  FOR THE YEAR ENDED DECEMBER 31, 2010
 ADDITIONS:Contributions:Employer
    
    $
    4,821,437Participant
    
    
    7,626,838Total contributions
    
    
    12,448,275Gain on Investments:Interest
    
    
    548,633Dividends
    
    
    1,862,721Net appreciation in fair value of investments
    
    
    7,099,344Total gain on investments
    
    
    9,510,698Interest on notes receivable from participants
    
    
    150,727Assets transferred in, net
    
    
    78,467,470Other Income
    
    
    1,668Total additions
    
    
    100,578,838DEDUCTIONS:Benefits paid to participants
    
    
    8,826,213Administrative expenses
    
    
    71,459Total deductions
    
    
    8,897,672NET INCREASE
    
    
    91,681,166NET ASSETS AVAILABLE FOR BENEFITS:BEGINNING OF YEAR
    
    
    106,537,738NET ASSETS AVAILABLE FOR BENEFITS:END OF YEAR
    
    $
    198,218,904
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GENON ENERGY UNION SAVINGS PLAN
 
 NOTES TO FINANCIAL STATEMENTS
 1.
    
    DESCRIPTION OF THE PLAN
 General 
   Eligibility 
   - 4 -




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Contributions 
  Participant Accounts 
 Investments 
 Vesting 
 Notes Receivable from Participants 
 Payment of Benefits 
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Forfeited Accounts 
  2.
    
    SIGNIFICANT ACCOUNTING POLICIES
 Basis of Financial Presentation 
 Notes Receivable from Participants 
 Adoption of New Accounting Guidance 
  Fully Benefit-Responsive Investment Contracts 
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Use of Estimates 
 Market Risk 
 Administrative Expenses 
 Payment of Benefits 
 Investment Valuation and Income Recognition 
  3.
    
    ASSETS TRANSFERRED TO AND FROM THE PLAN
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4.
    
    INVESTMENTS
  December 31,2010
    
    
    2009Mutual Funds:Neuberger Berman Genesis Trust
    
    $
    **
    
    
    $
    7,238,558Vanguard 500 Index Fund Signal Shares
    
    
    10,512,377
    
    
    
    **Vanguard 500 Index Fund Investor Shares
    
    
    **
    
    
    
    10,426,402Vanguard Total Bond Market Index Fund
Investor Shares
    
    
    **
    
    
    
    5,468,172Common/Collective Trust Fund:Vanguard Retirement Savings Trust *
    
    
    49,522,306
    
    
    
    18,531,498Common Stock Fund:GenOn Energy Stock Fund
    
    
    **
    
    
    
    5,491,644
 *
    
    The Vanguard Retirement Savings Trust, a fully benefit-responsive investment
contract, as listed above represents the contract value of the Plans investment.**
    
    Investment did not represent 5% or more of the Plans net assets at year end.  Net appreciationin fair value ofinvestmentsMutual funds
    
    $
    8,882,653Common stocks
    
    
    (1,783,309
    )$
    7,099,344
 5.
    
    FAIR VALUE MEASUREMENTS
   Mutual funds
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Common/collective trust fund
  Common stock funds
   Fair Value Measurements Using InputTypeLevel 1
    
    
    Level 2
    
    
    Level 3
    
    
    TotalCommon stock funds
    
    $
    4,339,608
    
    
    $
    
    
    
    $
    
    
    
    $
    4,339,608Mutual funds:Bond funds
    
    
    15,908,346
    
    
    
    
    
    
    
    
    
    
    
    15,908,346Balanced funds
    
    
    22,836,442
    
    
    
    
    
    
    
    
    
    
    
    22,836,442Domestic equity funds
    
    
    47,680,170
    
    
    
    
    
    
    
    
    
    
    
    47,680,170International equity funds
    
    
    12,410,369
    
    
    
    
    
    
    
    
    
    
    
    12,410,369Money market fund
    
    
    22,364
    
    
    
    
    
    
    
    
    
    
    
    22,364Common/collective trust fund
    
    
    
    
    
    
    51,552,340
    
    
    
    
    
    
    
    51,552,340Total
    
    $
    103,197,299
    
    
    $
    51,552,340
    
    
    $
    
    
    
    $
    154,749,639
  Fair Value Measurements Using InputTypeLevel 1
    
    
    Level 2
    
    
    Level 3
    
    
    TotalCommon stock funds
    
    $
    5,905,986
    
    
    $
    
    
    
    $
    
    
    
    $
    5,905,986Mutual funds:Bond funds
    
    
    10,159,742
    
    
    
    
    
    
    
    
    
    
    
    10,159,742Balanced funds
    
    
    18,518,578
    
    
    
    
    
    
    
    
    
    
    
    18,518,578Domestic equity funds
    
    
    38,924,875
    
    
    
    
    
    
    
    
    
    
    
    38,924,875International equity funds
    
    
    11,984,501
    
    
    
    
    
    
    
    
    
    
    
    11,984,501Money market fund
    
    
    21,235
    
    
    
    
    
    
    
    
    
    
    
    21,235Common/collective trust fund
    
    
    
    
    
    
    18,940,967
    
    
    
    
    
    
    
    18,940,967Total
    
    $
    85,514,917
    
    
    $
    18,940,967
    
    
    $
    
    
    
    $
    104,455,884
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6.
    
    PLAN TERMINATION
  7.
    
    RELATED PARTY TRANSACTIONS
  8.
    
    TAX STATUS
    - 10 -




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9.
    
    RECONCILIATION OF FINANCIAL STATEMENTS TO FORM 5500
  December 31,2010
    
    
    2009Net assets available for benefits per the financial statements
    
    $
    198,218,904
    
    
    $
    106,537,738Adjustment from contract value to fair value for fully
benefit-responsive investment contracts
    
    
    2,030,034
    
    
    
    409,469Participant loans deemed distributed
    
    
    (172,582
    )
    
    
    Net assets available for benefits per the Form 5500
    
    $
    200,076,356
    
    
    $
    106,947,207
  Year EndedDecember 31,2010Increase in net assets available for benefits per the financial statements
    
    $
    91,681,166Add: Change in adjustment from contract value to fair value for
fully benefit-responsive investment contracts
    
    
    1,620,565Less: Participant loans deemed distributed
    
    
    (172,582
    )Increase in net assets available for benefits per the Form 5500
    
    $
    93,129,149
 10.
    
    SUBSEQUENT EVENTS
  (1)
    
    The Plan was amended to provide for an automatic pre-tax contribution deferral
of 6% of eligible compensation for new participants, when no other election is made.
The automatic enrollment will become effective on the first day of the first full pay
period beginning 30 days after the eligible new employee has received notice of such
automatic enrollment.
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(2)
    
    The Plan was amended to freeze the GenOn Energy Stock Fund as of December 31,
2010 and to liquidate the GenOn Energy Stock Fund and the CenterPoint Energy Stock Fund
under the Plan by December 31, 2011.
 (3)
    
    Upon a participants entitlement to payment of benefits, the participant may
elect to receive full or partial lump-sum distributions in cash, provided that no
lump-sum distribution may be paid to the participant unless he has elected such
distribution pursuant to an election, in the form and manner prescribed by the plan
administrator. If the participant elects to receive a partial
distribution, then the amount distributed shall be charged to, and paid from, the
participants accounts on a pro-rata basis. The Plan will honor valid installment
payment elections made prior to January 1, 2011 under the former RRI Energy, Inc. Union
Savings Plan. No participant or beneficiary shall be eligible to elect to receive
installment payments on or after January 1, 2011.
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GENON ENERGY UNION SAVINGS PLAN
 
   
 ( a )
    
    ( b )
    
    ( c )
    
    ( d )
    
    ( e )Description of investment includingIdentity of issue, borrower, lessor or
    
    maturity date, rate of interest,similar party
    
    collateral, par, or maturity value
    
    Cost
    
    Current valueMutual Funds:American Funds: EuroPacific Growth Fund  Class R5
    
    Registered Investment Company
    
    **
    
    $
    4,299,284American Funds: Growth Fund of America  Class R5
    
    Registered Investment Company
    
    **
    
    
    965,278American Funds: New Perspective Fund  Class R5
    
    Registered Investment Company
    
    **
    
    
    2,723,414Artisan International Fund, Investor Class
    
    Registered Investment Company
    
    **
    
    
    818,368Davis New York Venture Fund  Class Y
    
    Registered Investment Company
    
    **
    
    
    404,076Dodge & Cox Balanced Fund
    
    Registered Investment Company
    
    **
    
    
    2,456,378Morgan Stanley Institutional Fund Trust Midcap Growth  Class I
    
    Registered Investment Company
    
    **
    
    
    4,835,759Neuberger Berman Genesis Fund, Institutional Class
    
    Registered Investment Company
    
    **
    
    
    7,976,854PIMCO Total Return Fund, Institutional Class
    
    Registered Investment Company
    
    **
    
    
    8,507,486T. Rowe Price Equity Income Fund, Retail Class
    
    Registered Investment Company
    
    **
    
    
    639,646T. Rowe Small-Cap Stock Fund
    
    Registered Investment Company
    
    **
    
    
    3,002,912Turner Small Cap Growth Fund  Class I Shares
    
    Registered Investment Company
    
    **
    
    
    3,338,004*
    
    Vanguard 500 Index Fund Signal Shares
    
    Registered Investment Company
    
    **
    
    
    10,512,377*
    
    Vanguard Capital Opportunity Fund Investor Shares
    
    Registered Investment Company
    
    **
    
    
    2,210,929*
    
    Vanguard Dividend Growth Fund
    
    Registered Investment Company
    
    **
    
    
    3,457,667*
    
    Vanguard Growth Equity Fund
    
    Registered Investment Company
    
    **
    
    
    3,009,157*
    
    Vanguard Inflation-Protected Securities Fund Investor Shares
    
    Registered Investment Company
    
    **
    
    
    629,658*
    
    Vanguard PRIMECAP Fund Investor Shares
    
    Registered Investment Company
    
    **
    
    
    1,030,187*
    
    Vanguard Prime Money Market Fund
    
    Registered Investment Company
    
    **
    
    
    22,364*
    
    Vanguard Target Retirement 2005 Fund
    
    Registered Investment Company
    
    **
    
    
    258,098*
    
    Vanguard Target Retirement 2010 Fund
    
    Registered Investment Company
    
    **
    
    
    782,137*
    
    Vanguard Target Retirement 2015 Fund
    
    Registered Investment Company
    
    **
    
    
    3,861,813*
    
    Vanguard Target Retirement 2020 Fund
    
    Registered Investment Company
    
    **
    
    
    1,687,764*
    
    Vanguard Target Retirement 2025 Fund
    
    Registered Investment Company
    
    **
    
    
    5,437,255*
    
    Vanguard Target Retirement 2030 Fund
    
    Registered Investment Company
    
    **
    
    
    1,109,550
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GENON ENERGY UNION SAVINGS PLAN
 
 
 ( a )
    
    ( b )
    
    ( c )
    
    ( d )
    
    ( e )Description of investment includingIdentity of issue, borrower, lessor or
    
    maturity date, rate of interest,similar party
    
    collateral, par, or maturity value
    
    Cost
    
    Current value*
    
    Vanguard Target Retirement 2035 Fund
    
    Registered Investment Company
    
    **
    
    
    2,991,835*
    
    Vanguard Target Retirement 2040 Fund
    
    Registered Investment Company
    
    **
    
    
    1,594,016*
    
    Vanguard Target Retirement 2045 Fund
    
    Registered Investment Company
    
    **
    
    
    1,613,704*
    
    Vanguard Target Retirement 2050 Fund
    
    Registered Investment Company
    
    **
    
    
    623,994*
    
    Vanguard Target Retirement 2055 Fund
    
    Registered Investment Company
    
    **
    
    
    238*
    
    Vanguard Target Retirement Income Fund
    
    Registered Investment Company
    
    **
    
    
    419,662*
    
    Vanguard Total Bond Market Index Fund Signal Shares
    
    Registered Investment Company
    
    **
    
    
    6,771,202*
    
    Vanguard Total International Stock Index Fund
    
    Registered Investment Company
    
    **
    
    
    4,569,302*
    
    Vanguard Total Stock Market Index Fund Signal Shares
    
    Registered Investment Company
    
    **
    
    
    3,692,671*
    
    Vanguard Windsor II Fund Investor Shares
    
    Registered Investment Company
    
    **
    
    
    2,604,652Common/Collective Trust Fund:*
    
    Vanguard Retirement Savings Trust IV
    
    Common/Collective Trust
    
    **
    
    
    51,552,340Common Stock Funds:CenterPoint Energy Stock Fund
    
    Company Stock Fund
    
    **
    
    
    336,795*
    
    GenOn Energy Stock Fund
    
    Company Stock Fund
    
    **
    
    
    4,002,813$
    154,749,639*
    
    Participant Loans
    
    Interest rates between 4.25% - 9.25%
    
    $0
    
    $
    3,218,439
 
 *
    
    Represents a party-in-interest.**
    
    Cost information has been omitted because all investments are participant-directed.  - 14 -




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GENON ENERGY UNION SAVINGS PLANBy
    
    /s/ DONNA BENEFIELDDonna BenefieldChairman of the Benefits Committee of GenOn
Energy Services, LLC, Plan Administrator   - 15 -