Central Bank Solvency and Inflation

The monetary base in the United States, defined as currency plus bank reserves, grew from about $800 billion in 2008 to $2 trillion in 2012, and to roughly $4 trillion at the end of 2014 (see chart below). Some commentators have viewed this increase in the monetary base as a sure harbinger of inflation. For example, one economist wrote that this “unprecedented expansion of the money supply could make the ’70s look benign.” These predictions of inflation rest on the monetarist argument that nominal income is proportional to the money supply. The fact that the money supply has expanded rapidly while real income has grown very modestly means that sooner or later prices will have to catch up. Most academic economists (from Cochrane to Krugman and Mankiw) disagree. The monetarist argument arguably applies only to non-interest-bearing central bank liabilities, but since October 2008 a large fraction of the monetary base has consisted of reserves that pay interest (the so-called IOER, or interest on excess reserves) and one linchpin of the Fed’s “policy normalization principles” consists precisely in raising the IOER along with the federal funds rate. Since reserves pay close to market interest rates, they are close substitutes for other short-term assets such as Treasury bills from a bank’s perspective. As long as the central bank can affect the return on these short-term assets by adjusting the IOER, controlling inflation with a large balance sheet seems no different than it was before the Great Recession.