The Federal Reserve’s efforts in conjunction with other agencies to prevent the failure of systemically important firms have been controversial at times. One view holds that intervening to prevent the failure of a financial firm is counterproductive, because it leads to erosion of market discipline and creates moral hazard. As a general matter, I agree that preserving market discipline is extremely important, and, accordingly, the government should intervene in markets only in exceptional circumstances. However, in my view, the failure of a major financial institution at a time when financial markets are already quite fragile poses too great a threat to financial and economic stability to be ignored. In such cases, intervention is necessary to protect the public interest. The problems of moral hazard and the existence of institutions that are “too big to fail” must certainly be addressed, but the right way to do this is through regulatory changes, improvements in the financial infrastructure, and other measures that will prevent a situation like this from recurring. Going forward, reforming the system to enhance stability and to address the problem of “too big to fail” should be a top priority for lawmakers and regulators.

In principle, our ability to pay interest on excess reserves at a rate equal to the funds rate target, as we have been doing, should keep the actual rate near the target, because banks should have no incentive to lend overnight funds at a rate lower than what they can receive from the Federal Reserve. In practice, however, several factors have served to depress the market rate below the target. One such factor is the presence in the market of large suppliers of funds, notably the government-sponsored enterprises (GSEs) Fannie Mae and Freddie Mac, which are not eligible to receive interest on reserves and are thus willing to lend overnight federal funds at rates below the target.

Banks have an incentive to borrow from the GSEs and then redeposit the funds at the Federal Reserve; as a result, banks earn a sure profit equal to the difference between the rate they pay the GSEs and the rate they receive on excess reserves. However, thus far, this type of arbitrage has not been occurring on a sufficient scale, perhaps because banks have not yet fully adjusted their reserve-management practices to take advantage of this opportunity.

Although conventional interest rate policy is constrained by the fact that nominal interest rates cannot fall below zero, the second arrow in the Federal Reserve’s quiver–the provision of liquidity–remains effective. Indeed, there are several means by which the Fed could influence financial conditions through the use of its balance sheet, beyond expanding our lending to financial institutions. First, the Fed could purchase longer-term Treasury or agency securities on the open market in substantial quantities. This approach might influence the yields on these securities, thus helping to spur aggregate demand. Indeed, last week the Fed announced plans to purchase up to $100 billion in GSE debt and up to $500 billion in GSE mortgage-backed securities over the next few quarters. It is encouraging that the announcement of that action was met by a fall in mortgage interest rates.