The Federal Reserve has been keeping the federal funds rate close to the interest rate on excess reserves since 2018. This has led banks to change how they operate, entering a new regime where they hold excess reserves and make wholesale loans. In this regime, banks are most responsive to changes in interest rates when it comes to lending to the public. However, they are less affected by policies like quantitative easing. The Fed can use the spread between these rates to influence how banks behave, which could help stabilize the economy during future recessions.