With euro zone leaders planning an emergency Greek debt summit on Monday, the chances of a reform-for-aid deal is probably 60 percent, former U.S. Deputy Treasury Secretary Roger Altman said Friday.
"I think the odds have narrowed," Altman told CNBC's "Squawk Box" following the failure of the region's finance ministers to reach an agreement this week. "But I still think the likelihood of a solution is greater than a blowup."
Greece has said that without further aid, it would be unable to make a $1.7 billion debt payment to the International Monetary Fund on June 30.
On Thursday, IMF chief Christine Lagarde raised the stakes—telling Athens there would be no grace period.
But Altman, a former Clinton administration official and Evercore Partners founder, remained skeptical. "These deadlines tend to be squishy," he said. "When push comes to shove, such deadlines often get extended."