Rohner, 44, is leaving after UBS admitted it made “mistakes” by helping clients evade U.S. taxes between 2000 and 2007. UBS has denied allegations in

DETROIT (Reuters) - General Motors Corp posted a loss of nearly $31 billion for 2008 and said its auditors were likely to cast doubt on its viability as it seeks an expanded federal bailout to stay afloat.

Revenue plunged by more than a third to $30.8 billion. GM burned through more than $5 billion in the fourth quarter and ended the year with $14 billion in cash, including the first $4 billion in loans it received from the U.S. Treasury.