There appears to be a consensus that the recent instability in global financial markets may be attributable in part to the failure of financial modeling. More specifically, current risk models have failed to properly assess the risks associated with large adverse stock price behavior. In this...

The single-index market model is estimated with market returns from mutual funds. Binary variables are used to determine if the beta coefficients increase during bull markets. If the mutual fund beta coefficients increase during bull markets, for example, this increase indicates the portfolio...