Image by Tony Crider via Flickr
The dollar's role as the world's dominant currency is coming under intense scrutiny.
This week, China added its voice to demands for a new global currency as an alternative to the dollar in international trade and finance.
It is worried that the dollar's value is being eroded by the steps the US is taking to rescue its economy from the worst financial crisis since the 1930s.
The US currency recorded its biggest weekly slide since 1985 last week, after the Federal Reserve said it would begin buying government debt to try to boost the economy, underscoring concerns.
"Calls for a new global currency come at a time when the US dollar is probably at its most vulnerable in many years," says Mitul Kotecha, global head of foreign exchange strategy at French financial services firm Calyon.