Fed analyzing negative rates in 'spirit' of prudent planning: Yellen

WASHINGTON (Reuters) - Federal Reserve Chair Janet Yellen said on Wednesday that the U.S. central bank is analyzing the prospect of negative interest rates in the spirit of prudent planning, but it is not a preferred option. She told a committee of lawmakers in Congress that given the implementation of negative rates by the Bank of Japan and the European Central Bank it is something U.S. policymakers look at in order to assess all the available tools. However, Yellen added that the Fed concluded negative rates was not a preferred tool when it last looked at the option in 2010, in part due to its impact on money markets. (Reporting by Lindsay Dunsmuir; Editing by Paul Simao)