This article studies the impact of exogenous legal change on whether and how lawyers across four different deal types revise their contracts’ governing law clauses in order to solve the problem that the legal change created. The governing law clause is present in practically every contract across a wide range of industries and, in particular, it appears in deals as disparate as private equity M&A transactions and sovereign bond issuances. Properly drafted, the clause increases the ex ante economic value of the contract to both parties by reducing uncertainty and litigation risk. We posit that different levels of agency costs are the motivating factors that influence beneficial innovations in governing law clauses as well as their mirror opposite, costly encrustations. Our data show that lawyers who draft private equity M&A deals pay more attention to the deal terms than lawyers producing corporate and sovereign bond contracts. Because agency costs are low in the private equity setting, we observe significantly more innovation in private equity deals as compared to sovereign and corporate bond transactions where the agency problems of drafting lawyers are much greater. More surprising, we also find that contracts drafted by private equity M&A lawyers have more obsolete and encrusted terms than the contracts of the other deal types. Our conjecture is that the lawyers' dominant drafting strategy is to find examples of a desired term in other documents and import that language verbatim into the contract together with other redundant and obsolete terms including, on occasion, terms that may harm the clients' interests if retained in the contract.