September 17, 2019 was a significant day in American economic history. On that day, the New York Federal Reserve began emergency cash infusions into the repurchasing (repo) market. This is the market banks use to make short-term loans to each other. The New York Fed acted after interest rates in the repo market rose to almost 10 percent, well above the Fed’s target rate. The New York Fed claimed its intervention was a temporary measure, but it has not stopped pumping money into the repo market since September. Also, the Federal Reserve has been expanding its balance sheet since September. Investment ...