Bank stocks suffered the most, hitting or nearing the daily trading limit of a 30 percent loss.

The Athens Stock Exchange and Greek banks were closed on June 29, when controls on money withdrawals and transfers were imposed to prevent a collapse in the banking system due to a run on deposits.

Banks have since reopened, while maintaining strict withdrawal limits.

Greece is currently in intense negotiations with bailout lenders in an effort to negotiate the terms of a massive new rescue package in the next two weeks.

Negotiators from the European Union and International Monetary Fund are seeking faster cuts in early retirement plans set out by the government, and stricter conditions for a tax arrears payment program.

Prime Minister Alexis Tsipras is facing opposition to the new bailout from within his left-wing Syriza party that could force him to call an early election in the fall.(AP)