Reply #6: The risk isn't Greece.

[Statistical]

If Greece implodes and it stops there it would be a non-issue.

However Greek economy has a lot of the same problems as Spain, Portugal, and Italy.
All 4 nations combined are about 20% of the Eurozone. Now we are talking about a larger risk.

Greece near failure has shaken confidence of bond investors in those other countries. If Greece can fail then Spain can fail too.
This makes it harder for Spain and other to refinance their debt which makes it harder for them to balance their budget.

If all 4 nations collapsed the fear is that it could bring down the EU and the fear then is that would bring down the world's economy.
China actually exports more to EU than the US. A massive slowdown in exports to EU would derail China and dominoes start falling.

So if Greece implodes on a macro-economic scale nobody really gives a flying crap. The fear is the contagion.

It is already spreading. Yields on Spainish debt in secondary market have increased 300 basis points since start of the year. If Spain can't refinance its debts at a reasonable interest rate (and has a lot coming due this year) then it will need a bailout too.