It may be a good time to invest in NBG, it has never been this low. It's really a 50/50 situation. If the Troika doesnt let Greece fall, whoever investing on NBG now will get pretty good returns, the problem is if the Greexit actually happens and your investment goes literally to 0. If you have something like 1K dollars lying around that you dont know where to put and you are already on Bitcoin, maybe a gamble with this may be a good investment if Greece recovers in the next 5 to 10 years.