The main purpose of this thesis is to discuss and examine the impact of the quantitative easing, which was implemented during the global financial crisis of 2008, to the financial assets and the economy and find, if any, the economic and financial effects it has had in the implementing countries. We discuss the unconventional monetary policies of the large four central banks; Federal Reserve (FED), European Central Bank (ECB), Bank of England (BOE) and Bank of Japan (BOJ) with a special emphasis in the Federal Reserve’s implementation policy in the United States of America.