In an “activist risk arbitrage,” a shareholder attempts to improve terms of an announced M&A through public campaigns. Activists target deals with low premiums and those susceptible to managerial conflicts of interest, including going‐private deals and deals in which CEOs receive outsized payments. Activist arbitrageurs are associated with a significant decrease in the probability that targets will be sold to the announced bidders, and an increase in the premium paid, both ex post among surviving deals and ex ante among all deals. Activist arbitrage serves as a governance mechanism in M&A and earns higher returns than passive arbitrage.

This paper studies the presence of hedge funds in the Chapter 11 process and their effects on bankruptcy outcomes. Hedge funds strategically choose positions in the capital structure where their actions could have a bigger impact on value. Their presence, especially as unsecured creditors, helps balance power between the debtor and secured creditors. Their effect on the debtor manifests in higher probabilities of the latter's loss of exclusive rights to file reorganization plans, CEO turnover, and adoptions of key employee retention plan, while their effect on secured creditors manifests in higher probabilities of emergence and payoffs to junior claims.