We analyze dynamic trading by an activist investor who can expend costly effort to affect firm value. We obtain the equilibrium in closed form for a general activism technology, including both binary and continuous outcomes. Variation in parameters can produce either positive or negative...

Using a comprehensive sample of trades from Schedule 13D filings by activist investors, we study how measures of adverse selection respond to informed trading. We find that on days when activists accumulate shares, measures of adverse selection and of stock illiquidity are lower, even though...

We analyze a dynamic model of informed trading where a shareholder accumulates shares in an anonymous market and then expends costly effort to change the firm value. We find that equilibrium prices are affected by the position accumulated by the shareholder, because the level of effort...