At meetings here in Washington, the group of twenty leading nations have been working on plans to deal with the potential damage from a Greek default.
A lot of their efforts have been focused on the banking system. If Greece were allowed to go bust, the bonds that banks hold would become worthless.
German and French banks are most at risk. So there's been lots of talk here in Washington on how to inject more capital to shore them up.
The other big worry is that if Greece defaulted, the financial markets would start turning on other countries. If Italy or Spain were to come under pressure, those here say there isn't enough cash available to help them.
That's why finance ministers are working on building a firewall around Greece to stop the situation from getting that far.
Michelle Fleury, BBC News
default failure - to pay back debts
to go bust - to go bankrupt, to have no money to pay debts
bonds - certificates of debt issued by a government or corporation
worthless - of no value
at risk - exposed to the possibility of losing money
to inject - to introduce, to put into
to shore them up - to support them
turning on - attacking or criticizing suddenly and unexpectedly
to come under pressure - to be affected by the crisis