"The sums involved are quite large, and no one knows quite how much of that gap the IMF can fill," said Philip Whyte, an economist at the Centre for European Reform in London. "Even 10 or 11 billion euros would be a big help," he said, but it would need to be supplemented by some form of European loan, bilateral or collective, particularly with Greece needing to roll over an additional $44 billion later this year.