Since the Financial Crisis of 2008, most reform measures and discussions have asked how the law of financial regulation could be improved to prevent or mitigate future crises. These discussions give short shrift to the role played by corporate law during the Financial Crisis of 2008 and other financial crises. One critical regulatory tool during the crisis was “regulation by deal,” in which healthy financial firms (“acquirers”) would hastily acquire failing firms (“targets”) to mitigate the crisis. The deals were governed by corporate law, so corporate law played an outsize role in the response to the crisis. But few observers have asked how corporate law—in addition to financial regulation—should govern dealmaking in financial crises. To fill in this gap, this Article focuses on the role played by corporate law during the Financial Crisis of 2008, and asks whether corporate law should be different during a financial crisis than in ordinary times. Using an externality framework—failure of a systemically important firm can harm the entire economy, and not just the shareholders of the failed firm—this Article identifies a key problem with the current corporate law regime as applied in financial crises: the shareholder value maximization principle as applied to failing target companies. This principle, manifested in the form of shareholder voting rights on mergers and board fiduciary duties to shareholders, is inapplicable to systemically important target firms whose failure would have enormous negative externalities on the rest of the economy. This Article contends that corporate law as applied to systemically important, failing target firms during crises should change as follows: (1) replace shareholder merger voting rights with appraisal rights, and (2) alter fiduciary duties so that directors and officers of those failing target firms consider the interests of the broader economy.