Empirical Evaluation of Investor Rationality in the Asset Allocation Puzzle

We examine the portfolio-choice puzzle posed by Canner, Mankiw, and Weil (1997). The idea is to test a conclusion reached by Elton and Gruber (2000), stating that a bonds/stocks ratio which decreases in relation to risk tolerance does not necessarily mean a contradiction of modern portfolio-choice theory and does not cast doubt on the rationality of investors. From data on the portfolio composition of 470 clients of a Canadian brokerage firm, we obtain that the bonds/stocks ratio does decrease in relation to risk tolerance. We also verify the existence of the two-fund separation theorem in the assets data available to the investors in our sample.