Fed balance sheet

The Economist looks at the Fed's profits from taking on risky assets.

Like Wall Street’s finest, the Fed makes money on a spread. Its main source of funds comes from issuing cash, since currency in circulation is, in effect, an interest-free loan by the public to the central bank. The interest it earns on its loans and securities is almost pure profit, or “seigniorage,” most of which it remits to the Treasury.