Commitments, Guarantees and Contingencies Commitments: We had unfunded off-balance sheet commitments to extend credit totaling $21.30 billion and $17.86 billion as of December 31, 2013 and 2012 , respectively. The potential losses associated with these commitments equal the gross contractual amounts, and do not consider the value of any collateral. Approximately 75% of our unfunded commitments to extend credit expire within one year from the date of issue. Since many of these commitments are expected to expire or renew without being drawn upon, the gross contractual amounts do not necessarily represent our future cash requirements. Guarantees: Off-balance sheet guarantees are composed of indemnified securities financing, stable value protection, unfunded commitments to purchase assets, and standby letters of credit. The potential losses associated with these guarantees equal the gross contractual amounts, and do not consider the value of any collateral. The following table presents the aggregate gross contractual amounts of our off-balance sheet guarantees as of December 31, 2013 and 2012 . Amounts presented do not reflect participations to independent third parties. (In millions) 2013 2012 Indemnified securities financing $ 320,078 $ 302,341 Stable value protection 24,906 33,512 Asset purchase agreements 4,685 5,063 Standby letters of credit 4,612 4,552 Indemnified Securities Financing On behalf of our clients, we lend their securities, as agent, to brokers and other institutions. In most circumstances, we indemnify our clients for the fair market value of those securities against a failure of the borrower to return such securities. We require the borrowers to maintain collateral in an amount equal to or in excess of 100% of the fair market value of the securities borrowed. Securities on loan and the collateral are revalued daily to determine if additional collateral is necessary or if excess collateral is required to be returned to the borrower. Collateral received in connection with our securities lending serv