Since 2006 the balance sheets of the eight largest central banks around the globe have nearly tripled--now totaling almost $15 trillion. Much of this explosion, seen in the chart below from Ritzholtz.com, can be attributed to asset purchases by the Fed, ECB, and BOJ, each of whom has sought new means of monetary easing with their benchmark rates near zero. A perspective on the sheer size of these balance sheets can be obtained by comparing their sum to the entire market capitalization of global equity markets. The $15 trillion held by major central banks is approximately 33% of the global equity market capitalization. In 2007 it was a mere 10%.