Who exactly foots the bill if Greece defaults Apologies if the topic is not appropriate (economics newbie here) but I am curious as to who exactly would foot the bill if Greece defaults on the ~300 billion dollars it owes. It looks like most of the money is owed to EU, IMF and ECB but what does that really mean in layman terms? Does it mean that tax-payers in other (mostly EU) countries end up paying one way or the other.
Who would pay depends on the terms of the default. Sometimes holders of similar debts are not treated equally, and this can play out in different ways. Greeks could default on external debts but continue to pay internal creditors. Or because the ESM and other entities are providing ongoing financing, perhaps they will continue to be repaid when others are not to keep those spigots open. Or, less extremely, they could vary the degree of forbearance, term changes, and extent of default. 

I found the following two charts from 2013 and 2014 helpful for understanding who are the current holders of Greek public debt and how that compares with other rich countries.




Source: STARLING CITY  

Update:
I couldn't find a time series of the holders of Greek debt but here are some additional charts to see the evolution. The first one is more comparable to the pie chart above than the second one which shows only bank holdings. If this is of interest, the BIS's consolidated banking statistics could be used to create a time series of the bank holdings of Greek debt