residential mortgage-backed securities at december 31 , 2012 , our residential mortgage-backed securities portfolio was comprised of $ 31.4 billion fair value of us government agency-backed securities and $ 6.1 billion fair value of non-agency ( private issuer ) securities . the agency securities are generally collateralized by 1-4 family , conforming , fixed-rate residential mortgages . the non-agency securities are also generally collateralized by 1-4 family residential mortgages . the mortgage loans underlying the non-agency securities are generally non-conforming ( i.e. , original balances in excess of the amount qualifying for agency securities ) and predominately have interest rates that are fixed for a period of time , after which the rate adjusts to a floating rate based upon a contractual spread that is indexed to a market rate ( i.e. , a 201chybrid arm 201d ) , or interest rates that are fixed for the term of the loan . substantially all of the non-agency securities are senior tranches in the securitization structure and at origination had credit protection in the form of credit enhancement , over- collateralization and/or excess spread accounts . during 2012 , we recorded otti credit losses of $ 99 million on non-agency residential mortgage-backed securities . all of the losses were associated with securities rated below investment grade . as of december 31 , 2012 , the noncredit portion of impairment recorded in accumulated other comprehensive income for non-agency residential mortgage- backed securities for which we have recorded an otti credit loss totaled $ 150 million and the related securities had a fair value of $ 3.7 billion . the fair value of sub-investment grade investment securities for which we have not recorded an otti credit loss as of december 31 , 2012 totaled $ 1.9 billion , with unrealized net gains of $ 114 million . commercial mortgage-backed securities the fair value of the non-agency commercial mortgage- backed securities portfolio was $ 5.9 billion at december 31 , 2012 and consisted of fixed-rate , private-issuer securities collateralized by non-residential properties , primarily retail properties , office buildings , and multi-family housing . the agency commercial mortgage-backed securities portfolio was $ 2.0 billion fair value at december 31 , 2012 consisting of multi-family housing . substantially all of the securities are the most senior tranches in the subordination structure . there were no otti credit losses on commercial mortgage- backed securities during 2012 . asset-backed securities the fair value of the asset-backed securities portfolio was $ 6.5 billion at december 31 , 2012 and consisted of fixed-rate and floating-rate , private-issuer securities collateralized primarily by various consumer credit products , including residential mortgage loans , credit cards , automobile loans , and student loans . substantially all of the securities are senior tranches in the securitization structure and have credit protection in the form of credit enhancement , over-collateralization and/or excess spread accounts . we recorded otti credit losses of $ 11 million on asset- backed securities during 2012 . all of the securities are collateralized by first lien and second lien residential mortgage loans and are rated below investment grade . as of december 31 , 2012 , the noncredit portion of impairment recorded in accumulated other comprehensive income for asset-backed securities for which we have recorded an otti credit loss totaled $ 52 million and the related securities had a fair value of $ 603 million . for the sub-investment grade investment securities ( available for sale and held to maturity ) for which we have not recorded an otti loss through december 31 , 2012 , the fair value was $ 47 million , with unrealized net losses of $ 3 million . the results of our security-level assessments indicate that we will recover the cost basis of these securities . note 8 investment securities in the notes to consolidated financial statements in item 8 of this report provides additional information on otti losses and further detail regarding our process for assessing otti . if current housing and economic conditions were to worsen , and if market volatility and illiquidity were to worsen , or if market interest rates were to increase appreciably , the valuation of our investment securities portfolio could be adversely affected and we could incur additional otti credit losses that would impact our consolidated income statement . loans held for sale table 15 : loans held for sale in millions december 31 december 31 .
commercial mortgage loans held for sale designated at fair value at december 31 , 2011 were what percent of total loans held for sale at december 31 , 2011?
we stopped originating commercial mortgage loans held for sale designated at fair value in 2008 and continue pursuing opportunities to reduce these positions at appropriate prices . at december 31 , 2012 , the balance relating to these loans was $ 772 million , compared to $ 843 million at december 31 , 2011 . we sold $ 32 million in unpaid principal balances of these commercial mortgage loans held for sale carried at fair value in 2012 and sold $ 25 million in 2011 . the pnc financial services group , inc . 2013 form 10-k 49 .