This excerpt taken from the C 10-Q filed May 11, 2009.
Non-Credit Accretion on Reclassified Assets
In the fourth quarter of 2008, the Company reclassified $33.3 billion of debt securities from trading securities to HTM investments, $4.7 billion of debt securities from trading securities to AFS, and $15.7 billion of loans from held-for-sale to held-for-investment. All assets were reclassified with an amortized cost equal to the fair value on the date of reclassification. The difference between the amortized cost basis and the expected principal cash flows is treated as a purchase discount and accreted into income over the remaining life of the security or loan. In the first quarter of 2009, the Company recognized approximately $541 million of interest revenue based on this accretion.