This dissertation contributes to the on-going discussion about the role of informed trading in the formation of efficient security prices. In Chapter II, I examine the pre-announcement periods with the temporary increases in informed trading. The findings suggest that the market can detect the...

Shares trading in the Bolsa mexicana de Valores do not seem to react to company news. Using a sample of Mexican corporate news announcements from the period July 1994 through June 1996, this paper finds that there is nothing unusual about returns, volatility of returns, volume of trade or...

We characterize how informed investors trade in the options market ahead of corporate news when they receive private, but noisy, information about (i) the timing of the announcement and (ii) its impact on stock prices. Our theoretical framework generates a rich set of predictions about the...