If Greece fails to make payment, Mr. Weinberg said, the country could be declared either in arrears or in default, with such a determination taking several days.

That's not what Christine Lagarde, Managing Director of the IMF says. She said last Thursday that if Greece did not make the payment due on the 30th they would be in default right away. There was to be no grace period because they are lumping their loans together from the month.

Greek officials have already said they will not be making that payment.

Then it is up to the ECB to say whether their loans will all become due instantly as well since then Greece will be in violation of their policies.

. . . and so on.