The WSJ article Greece Teeters as Talks Fail claims that:
In a potent sign of Greeks’ rising anxiety, depositors withdrew €700 million ($898 million) from local banks on Monday alone, according to the country’s national bank—a significant escalation in capital flight from the country.
A worrying portent. This is how bank runs develop – and how currency unions end.
If there is any hesitation on the part of the ECB in the provision of an elastic currency, a run is likely to develop, and this may test the European Core’s appetite for Greek liabilities.