We study a dynamic contracting problem in which size is relevant. The agent may take on excessive risk to enhance short-term gains, which exposes the principal to large, infrequent losses. To preserve incentive compatibility, the optimal contract uses size as an instrument; there is downsizing...

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...