ABSTRACT. Trebilcock and Leng say that three non-state institutions of contract enforcement are utilized extensively to mitigate contracting problems arising from cross-border transactions: international commercial arbitration, transnational business and social networks, and barter/countertrade. Katz writes that, in some cases, contracting costs may be substantial and default rules will have the effect of privileging one substantive outcome rather than others. Nunn holds that when investments are relationship-specific, underinvestment will occur if contracts cannot be enforced.