How effective was Quantitative Easing 3 (QE3) in stimulating business investment? Although the link between the financial market and the business sector is often discussed, the precise numerical relationship between financial and business investment is not well understood. In this paper, the “Investment Realization Ratio” is devised for the purpose of elucidating this relationship by quantifying the percentage of funds entering into the financial market that actually translates into business investment. We estimate that the amount of business investment stimulated by QE3 is only a fraction of the amount of bonds purchased by the Fed; this fraction is called the “Investment Realization Ratio.” large-scale asset purchases, unconventional monetary policy, business investment.