Reliable estimates of variances and covariances are crucial for portfolio management and risk controlling. This paper investigates alternative methods to estimate time varying variance-covariance matrices: ordinary estimates and exponentially weighted moving averages in comparison to Markov...

This study proposes a wavelet procedure for estimating partial correlation coefficients between stock market returns over different time scales. The estimated partial correlations are subsequently used in a cluster analysis to identify, for each time scale, groups of stocks that exhibit distinct...

Discount rates affect stock prices directly via the discount-rate channel or indirectly via the cash-flow channel because expected future cash-flow growth varies with the discount rates. The traditional Macaulay duration captures the effect from the discount-rate channel. I propose a novel...

This paper proposes a new approach to control the effects of time-varying parameters on the estimates of abnormal returns. Event studies usually assume that the parameters of the market model are stable. Using a sample of firm takeovers, however, I find that this assumption is indeed rejected....