Contract scholarship has given little attention to the production process for contracts. The usual assumption is that the parties will construct the contract ex nihilo, choosing all the terms so that they will maximize the surplus from the contract. In fact, parties draft most contracts by slightly modifying the terms of contracts that they have used in the past, or that other parties have used in related transactions. A small literature on boilerplate recognizes this phenomenon, but little empirical work examines the process. This Article provides an empirical analysis by drawing on a dataset of sovereign bonds. We show that exogenous factors are key determinants in the evolution of these contracts. We find an evolutionary pattern that roughly separates into three stages: stage one when a particular standard form dominates in the absence of external shocks; stage two when there are external shocks and marginal players experimenting with deviations from the standard form; and stage three when a new standard emerges. We find that more marginal law firms are likely to be leaders in innovation at early stages of the innovation cycle but that dominant law firms are leaders at later stages.