Jan Loeys, chief market strategist at JP Morgan says in an investor note on Greece and the euro:

"The risk scenario of Greek exit from the EMU is a drama for Greece, but in this analyst's view, not for world markets

Claims on Greece are concentrated at the European Central Bank and EU institutions"

He is quoted in a Bloomberg article, which includes similar from other analysits:

"The euro's collapse is unlikely because markets have already priced in such risks. The Greek problem isn't shaking up Italy and Spain."

More at that link