In March 2020, banks faced the largest increase in liquidity demands ever observed. Firms drew funds on a massive scale from preexisting credit lines in anticipation of cash flow and financial disruptions stemming from the advent of the COVID-19 crisis. The increase in liquidity demands was concentrated at the largest banks, who serve the largest firms. Precrisis financial condition did not constrain large banks’ liquidity supply. Coincident inflows of funds from both the Federal Reserve’s liquidity injection programs and depositors, along with strong preshock bank capital, explain why banks were able to accommodate these liquidity demands. (JEL G21, G28) Received June 7, 2020; editorial decision June 23, 2020 by Editor Isil Erel.

Liquidity restrictions on investors, like the redemption gates and liquidity fees introduced in the 2016 money market fund (MMF) reform, are meant to improve financial stability. However, we find evidence that such liquidity restrictions exacerbated the run on prime MMFs during the COVID-19 crisis. Our results indicate that gates and fees could generate strategic complementarities among investors in crisis times. Severe outflows from prime MMFs led the Federal Reserve to intervene with the Money Market Mutual Fund Liquidity Facility (MMLF). Using MMLF microdata, we show how the provision of “liquidity of last resort” stabilized prime funds.