This is a joint post by Mark Weidemaier and Mitu Gulati.
About a decade and a half ago, exit consents were a big deal in sovereign debt restructuring. At the time, sovereign bonds governed by New York law required unanimous bondholder approval before any modification to the payment terms of the bonds. The result was that creditors could easily hold out from a restructuring. Needing to mitigate the holdout problem in Ecuador in 2000, sovereign debt guru Lee Buchheit borrowed a technique from corporate bond restructuring practice in the United States. There, the Trust Indenture Act forbids out-of-court bond exchanges that modify "the right of any holder ... to receive payment ... or to institute suit" without the consent of each affected bondholder. To oversimplify, Buchheit leveraged the fact that other terms of the bonds could be amended with a lesser vote, often a simple majority or 66.67% of the bonds. This meant that potential holdouts risked having key protections stripped from their bonds in a restructuring that won the approval of a majority of bondholders.