Why Has the Fed's Money Printing Not Stimulated the Economy? Over 80% of Those Dollars Are Sitting in Banks and Not Being Lent Out or Invested

A pretty good explanation as to why Bernanke's massive money printing has failed to produce the desired effect:

Although the Bernanke Fed has disbursed $2.284 trillion in new money (the monetary base) since August 1, 2008, one month before the 2008 financial crisis, 81.5 percent now sits idle as excess reserves in private banks. The banks are not required to hold excess reserves. The excess reserves exploded from $831 billion in August 2008 to $1.863 trillion on June 14, 2013. The excess reserves of the nation's private banks had previously stayed at nearly zero since 1959 as seen on the St. Louis Fed's chart. The banks did not leave money idle in excess reserves at zero interest because they were investing in income earning assets, including loans to consumers and businesses.

This 81.5 percent explosion in idle excess reserves means that the Bernanke Fed's new money issues of $85 billion each month have never been a big stimulus. Approximately 81.5 percent (or $69.27 billion) is either bought by banks or deposited into banks where it sits idle as excess reserves. The rest of the $85 billion, approximately 18.5 percent (or $15.72 billion) continues to circulate or is held as required reserves on banks' deposit accounts (unlike unrequired excess reserves).

One reason that the excess reserves grew to an extraordinary level is that in October 2008, one month after the financial crisis when Lehman Brothers went bankrupt, the Bernanke Fed began paying interest on bank reserves. Although it has been 1/4 of 1 percent interest, this risk free rate was not low compared to the Fed's policy of keeping short-term market rates near zero. The interest banks received was and is an incentive to hold the excess reserves rather than lend to consumers and businesses in the risky environment of the major recession and the slow recovery.

The Bernanke Fed is now facing a $1.863 trillion time bomb, they helped to create, of excess reserves in the private banking system. If rates of interest on income earning assets (including bank loans to consumers and businesses) rise, the Fed will have to pay the banks more interest to hold their excess reserves.

At the current level of the time bomb, raising interest paid to banks on excess reserves would give the banks $18.6 billion a year at 1 percent interest, $55.9 billion a year at 3 percent interest and $93.2 billion a year at 5 percent interest. Because of concentration in banking, it is unlikely that much of the interest would be passed on to depositors. Bank stockholders would receive much of these large bonuses from the government.
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Eighty five billion a month will seem tiny compared to the avalanche of the $1.863 trillion excess reserves exploding rapidly into the economy. That would devalue the currency, cause more rapid inflation and worry investors about a coming collapse.