Powell said asset purchases could help bring down interest rates, but the effects are uncertain.

Sina Finance news on March 30th, Federal Reserve Chairman Powell defended the Fed's asset purchase policy on Monday, while acknowledging that there is still uncertainty about its actual effects on the economy. He stated in a speech at Harvard University that during times of market stress, the Fed's asset purchases "have not yet truly seen downside risks." He stated, "Purchasing long-term assets does lower interest rates and provide some support for economic activity."