TheFinancial Times-looked at whether central banks like the Federal Reserve can go bankrupt. The answer was no, but there are effects. It quotes from a paper by Seth Carpenter at Morgan Stanley:
Central bank profits and losses matter . . . but only when they matter. Before the 1900s, the subject of economics was called “political economy.” Central bank losses that affect fiscal outcomes may have political ramifications, but the banks’ ability to conduct policy is not impaired . . . . . .
Starting with the Fed, all the income generated on the System Open Market Account portfolio, less interest expense, realized losses, and operating costs is remitted to the US Treasury. Before the Global Financial Crisis, these remittances averaged $20-25 billion per year; they ballooned to more than $100 billion as the balance sheet grew. These remittances reduce the deficit and borrowing needs. Net income depends on the (mostly fixed) average coupon on assets, the share of liabilities that are interest free (physical paper currency), and the level of reserves and reverse repo balances, whose costs float with the policy rate. From essentially zero in 2007, interest-bearing liabilities have mushroomed to almost two-thirds of the balance sheet.
As the chart below shows, the US central bank’s net income (which have been passed back to the US Treasury) has turned negative, and Morgan Stanley forecasts the losses will rise as interest rates rise.