Here are the broadest measures of the US money supply, M3 and M4 as estimated by the Center for Fiscal Stability:
With the total money supply still at an absolute level lower than its 2008 peak, it is obvious that the Federal Reserve in tripling the monetary base — an expansion by what is in comparison to other components of M4 a relatively small amount — has been battling staggering deflationary forces. And with the money supply still lower than the 2008 peak and far-below its pre-2008 trend, the Fed is arguably struggling in this battle (even though by the most widely-recognised measure, the CPI-U the Fed has kept the US economy out of deflation).
Those who have pointed to massively inflationary forces in the American economy based on a tripling of the monetary base, or even expansion of M2 clearly do not understand that the Fed does not control the money supply. It controls the monetary base, which influences the money supply but the big money in the US economy is created endogenously through credit-creation by traditional banks and shadow banks. The Fed can lead the horse to water by expanding the monetary base, but in such depressionary economic conditions it cannot make the horse drink.
What does this imply? Well, either the monetary transmission mechanism is broken, or monetary policy at the zero bound is ineffectual.
What it also implies is that hyperinflation (and even high inflation) remains the remotest of remote possibilities in the short and medium terms. The overwhelming trend remains deflationary following the bursting of the shadow intermediation bubble in 2008, and to offset this powerful deflationary trend the Fed is highly likely to have to continue to prime the monetary pump Abenomics-style into the foreseeable future.