My suggested framework for Fed policy regarding asset-market instability can be summarized by the adage, Use the right tool for the job.
As you know, the Fed has two broad sets of responsibilities. First, the Fed has a mandate from the Congress to promote a healthy economy--specifically, maximum sustainable employment, stable prices, and moderate long-term interest rates. Second, since its founding the Fed has been entrusted with the responsibility of helping to ensure the stability of the financial system. The Fed likewise has two broad sets of policy tools: It makes monetary policy, which today we think of primarily in terms of the setting of the overnight interest rate, the federal funds rate. And, second, the Fed has a range of powers with respect to financial institutions, including rule-making powers, supervisory oversight, and a lender-of-last resort function made operational by the Fed's ability to lend through its discount window. By using the right tool for the job, I mean that, as a general rule, the Fed will do best by focusing its monetary policy instruments on achieving its macro goals--price stability and maximum sustainable employment--while using its regulatory, supervisory, and lender-of-last resort powers to help ensure financial stability.