We study return predictability using a model of speculative trading among relatively overconfident competitive traders who agree to disagree about the precision of their private information. Although traders apply Bayes Law consistently, returns are predictable. In addition to trading on...

This paper studies invariance relationships in tick-by-tick transaction data in the U.S. stock market. Over the 1993–2001 period, the estimated monthly regression coefficients of the log of trade arrival rate on the log of trading activity have an almost constant value of 0.666, strikingly...