Europe's central banks are intensifying efforts to jolt credit markets back to life.

The European Central Bank on Wednesday said it will accept lower-rated securities as collateral when lending to banks and offer them as many euros as they want over the next six months. The Swiss central bank said it will conduct currency swaps with the ECB, which today said it will also support the Hungarian central bank's money-market operations. The Bank of England will unveil plans to revamp its market operations at 11 a.m. in London.

"Central banks are throwing everything they can at the credit markets to get them working again," said Win Thin, an economist at Brown Brothers Harriman & Co in New York.