Delta Air Lines reported an $8.5 billion fourth-quarter net income,

boosted by an $8 billion gain "associated with the reversal of the company's tax valuation allowance." Absent special items, Delta posted an $558 million net profit for the December quarter. Fourth-quarter passenger revenue rose 6 percent year over year, with unit revenue up 3 percent. Delta posted a 4 percent increase in yield, a representation of fare paid per mile. Quarterly traffic rose 2 percent year over year on 3 percent additional capacity.