Fed's Powell says Fed balance sheet a viable tool

NEW YORK, March 30 (Reuters) - Federal Reserve Chair Jerome Powell defended the use of central bank asset buying Monday while acknowledging there’s uncertainty how much it helps the economy.

When it comes to central bank asset buying in times of acute stress “we haven't really seen the downside risks,” Powell said while speaking at Harvard University. “Buying long-term assets does…lower interest rates and does provide some support for economic activity,” he said.