Innovation commercialization phase appears more and more as an issue for both marketing and innovation management literatures. This paper studies a particular aspect of innovation commercialization, namely the market-model design activities occurring during this phase. The paper builds on an underlying paradox of the literature. On a one hand consistent market models are useful for company to commercialize innovation and on the other hand marketization literature claims that the relevant variables depicting a market are countless and unknown. To sort out how market-modeling activities support innovation commercialization we conducted seven longitudinal historical case studies on commercial travellers. We looked for how 19 th century companies employing commercial travellers structured their market models to foster commercialization excellence. Our results indicate that these companies used representations of the market that can be define as ad hoc market models. The representations are models as they are built only on few coherent variables but they are ad hoc as they differ from one case to another. Given these results we discuss the specificities of the design of ad hoc market models and define the innovation commercialization phase as the market-model design phase.