"This paper finds strong evidence of time-variations in the joint distribution of returns on a stock market portfolio and portfolios tracking size--and value effects. Mean returns, volatilities and correlations between these equity portfolios are found to be driven by underlying regimes that...

"Campbell and Vuolteenaho (2004) and Brennan, Wang, and Xia (2004) recently argue that the value premium co-moves with investment opportunities and thus reflects rational pricing. This paper extends their analysis by showing that the ICAPM interpretation of the value premium also sheds light on...