Moody's just cut the credit rating for Greece to Caa3 from Caa2. "The key driver for today's rating action is Moody's view that the probability of support continuing to be provided over the medium-term has fallen since the assignment of the Caa2 rating in April, regardless of the outcome of Sunday's referendum," the debt rating agency said. "Moody's believes that without ongoing support from official creditors, Greece will default on its privately-held debt." More to come...Join the conversation about this story » NOW WATCH: 6 scientifically proven features men find attractive in women