Abstract: Reverse termination fees (RTFs) are required payments for bidders to “walk away” from a merger or acquisition, and vary significantly in size and design, even within apparently similar deals. Using a large sample of manually collected U.S. deal contracts involving publicly traded bidders and targets, we examine the impact of different types of RTFs. Consistent with efficient contract theory, we find that inefficient RTF sizes and triggers correlate with significantly lower bidder abnormal returns, while efficient RTF sizes and triggers correlate with significantly higher bidder abnormal returns. Consistent with signaling theory, we also find evidence that the inclusion of some RTF triggers in the merger agreements reveals private information to the market, correlating with significant abnormal returns. Our findings have implications for how practitioners approach the design and negotiation of RTFs.