The Greek stock market is suffering a second day of losses since reopening, with banks shares down the most.

The main index was down 4 percent soon after the start of trading Tuesday. It fell 16.2 percent Monday, when it reopened after a five-week closure.

The plunge comes as Greece reels from the impact of limits on money withdrawals and transfers imposed June 29 to avoid a banking collapse as well as uncertainty over its negotiations for a new bailout.

Greece's government is relying on opposition party support for approval of new austerity measures demanded by bailout lenders, following a revolt by nearly one-fourth of its own lawmakers.

Government spokeswoman Olga Gerovasili said the government would not form a national unity government and described early elections as "likely."