This chapter examines the migration and translation of so-called “equilibrium” interest rate term structure models from academic financial economics into the over-the-counter (OTC) derivatives markets during the 1980s and 1990s. Initially developed to understand the economic factors that shape the pricing of bonds, these models underwent significant change to align with the modelling culture of derivatives practitioners as they migrated into the OTC derivatives markets. Using document analysis and interviews with quants and financial mathematicians, this study highlights the interplay between model stability and flexibility. It emphasizes that successful model migration involves iterative translations that maintain theoretical commensurability while adapting to new domains. The findings suggest that understanding the performativity of financial models requires examining the translation processes that enable models to reflect and integrate into the institutional contexts of their application. This case contributes to the Social Studies of Finance and the Philosophy of Science by demonstrating how model migration is facilitated by the translation of models into new forms that align with the organizational and practical realities of their target domains.