"The need to restructure the periphery and the quite reasonable demand that bondholders take pain will, in my view, happen," said Swenson. "It's not a radical view and yet prices of all non-Greek bonds seem to be too optimistic.
Al Moniz, portfolio manager at Fore Research & Management LP, a New York-based hedge fund with $1.9 billion under management, said he is "very bearish" on European sovereign debt and the region's banks, though he declined to say how he was positioning his portfolio to take advantage of that weakness.
"We are still in the early stages of the European crisis," he said. "It hasn't even been 30 percent played out."