A senior G20 source reportedly told Reuters, ""The central banks are preparing for coordinated action to provide liquidity," in the event that the Greek election wreak havoc in the markets.

Late last month, Business Insider first reported that rumors of coordinated central bank action had been circulating among traders and their sources, leading one analyst to assure us that such a liquidity-providing move was "a lock."

While these latest reports are nothing more than rumors, it would appear that pressure for coordinated central bank action—likely through an expansion of the dollar swap agreements put in place last November—is mounting.