TCF Financial ( TCB ), the Minnesota-based holding company for TCF National Bank, said earnings slipped from a year ago due to a rise in its noninterest expense. The company earned $65.5 million, or 50 cents a share, in the quarter, compared with earnings of $67.4 million, or 50 cents a share, a year ago. The number of average diluted shares outstanding fell by 2.8%, year over year. Fourth-quarter revenue totaled $254.3 million. Analysts were forecasting earnings of 49 cents a share on revenue of $254.5 million, according to Thomson First Call. Net interest income, the difference between what a bank makes on its investments and loans and the money it pays out to depositors, was up 2.2% to $129.2 million from $126.5 million. Net interest margin, a measure of the profitability of a bank's deposit and investment operation, dropped to 4.31% for this quarter from 4.56% a year ago. Total non-interest income in the fourth quarter of 2005 was $125 million, down $7.4 million, or 5.6%.