Before March 26, 2020, The Federal Reserve required banks to maintain a minimum reserve of approximately 10 percent of their deposits. But the threat the COVID pandemic imposed on the economy convinced policymakers at the Fed to drop the reserve requirement to encourage lending and prevent a severe recession. The reserve requirement is one of the tools a central bank can use to manage a nation’s money supply under a fractional reserve banking system. Deposits exceeding the reserve requirement are excess reserves, which banks can lend. When a central bank raises its reserve requirement, it reduces the amount a regulated bank has in excess reserves, which means it can lend less money to its customers.
For example, assume First Community Bank holds $1.0 million in customer deposits. The central bank sets the reserve requirement at ten percent. First Community must maintain a minimum balance of $100,000 (ten percent) in its vaults or on deposit with the central bank. It can lend the remaining $900,000, which is its excess reserves. Assume the central bank increases its reserve requirement to 15 percent. First Community would be required to increase its reserve deposits to $150,000 and reduce its lending to $850,000. Because the reserve requirement affects the amount of money banks are permitted to lend, it also affects the growth in the money supply or money multiplier. The money multiplier estimates the amount the money supply increases following an increase in reserves. The reserve requirement has an indirect relationship with the money multiplier. The above example illustrates that banks have more money to lend if they store less money in reserves. The maximum increase or monetary multiplier can be calculated using the formula below, where MM is the monetary multiplier and RR is the reserve requirement.
MM = 1 / RR
MM = 1 / .15
MM = 6.667
$1,000 x 6.667 = $6,667
MM = (1+ LR)
Increasing the reserve requirement slows the money supply’s growth because less money is available to lend. Reducing the reserve requirement expands the money supply by encouraging banks to lend more. The Fed does not change the reserve requirement frequently.(RR + LR)