With Greek PM Alexis Tsipras seemingly determined to take negotiations over pension reform and VAT hikes down to the "Zambian" bundle wire on June 30, and with the IMF having shrugged its shoulders, sighed, and traveled back to Washington, EU officials are now formally discussing what formerly was not to be mentioned in polite circles: a Greek 'Plan B'.

Senior EU officials have formally discussed for the first time a possible Greek debt default as negotiations between Athens and its creditors have stalled ahead of an end-month repayment deadline, several officials told Reuters.

The government representatives, preparing next week's Eurogroup meeting of euro zone finance ministers, concluded at talks in Bratislava late on Thursday that there were three possible scenarios for what would happen with Greece at the end of June. The least likely, they think, is a successful cash-for-reform deal next week in time to meet end-June legal deadlines.