We integrate appealing features of Markowitz’s mean-variance portfolio theory (MVT) and Shefrin and Statman’s behavioral portfolio theory (BPT) into a new mental accounting (MA) framework. Features of the MA framework include an MA structure of portfolios, a definition of risk as the...

We develop a positive behavioral portfolio theory (BPT) and explore its implications for portfolio constrution and security design. The optimal portfolios of BPT investors resemble combinations of bonds and lotterly tickets consistent with Friedman and Savage's (1948) observation. We compare the...

We show that a well-diversified portfolio of randomly chosen stocks must include at least 30 stocks for a borrowing investor and 40 stocks for a lending investor. This contradicts the widely accepted notion that the benefits of diversification are virtually exhausted when a portfolio contains...

This paper develops a capital asset pricing theory in a market where noise traders interact with information traders. Noise traders are traders who commit cognitive errors while information traders are free of cognitive errors. The theory includes the determination of the mean-variance efficient...