82%. Cornelli and Li contend that arbitrageurs are actually the most important element in determining the success of a merger. Since arbitrageurs have made significant financial bets that the merger will go through, it is expected that they will push for consummation. For this very reason, the probability that the merger will consummate increases as arbitrageur control increases. In their study, Cornelli and Li found that the arbitrage industry would hold as much as 30%-40% of a target's stock during the merger process. This represents a significant portion of the shares required to vote yes to deal consummation in most mergers. Thus, takeovers in which arbitrageurs bought shares had an actual success rate higher than the average probability of success implied by market prices. As a result, they can generate substantial positive returns on their portfolio positions. Active vs. passive risk arbitrage The arbitrageur can generate returns either actively or passively. Active arbitrageurs purchase enough stock in the target to control the outcome of the merger. These activist investors initiate sales processes or hold back support from ongoing mergers in attempts to solicit a higher bid. On the other end of the spectrum, passive arbitrageurs do not influence the outcome of the merger. One set of passive arbitrageurs invests in deals that the market expects to succeed and increases holdings if the probability of success improves. The other set of passive arbitrageurs is more involved, but passive nonetheless: these arbitrageurs are more selective with their investments, meticulously testing assumptions on the risk-reward profile of individual deals. This set of arbitrageurs will invest in deals in which they conclude that the probability of success is greater than what the spread implies. Passive arbitrageurs have more freedom in very liquid stocks: the more liquid the target stock, the better risk arbitrageurs can hide their trade. In this case, using the assumption that a higher arbitrageur presence increases the probability of consummation, the share price will not fully reflect the increased probability of success and the risk arbitrageur can buy shares and make a profit. The arbitrageur must decide whether an active role or a passive role in the merger is the more attractive option in a given situation. Risk-return profile The risk-return profile in risk arbitrage is relatively asymmetric. There is typically a far greater downside if the deal breaks than there is upside if the deal is completed. Deal-level risks Risk