The Education Department's inspector general said Monday [1] that Sallie Mae had overbilled the U.S. Treasury by $22.3 million in payments made to its Nellie Mae subsidiary from 2003 to 2006. The company inappropriately sought reimbursement from the government for loans financed with tax-exempt bonds, even though the bonds had matured, the inspector general found; Sallie Mae disputed the finding. The lender is the latest in a string [2] of loan providers that the inspector general has found [3] to have abused the tax-exempt bond program, although the Bush administration's Education Department required only one of the lenders, Nelnet, to return the disputed funds.