In Becker's (1973) neoclassical marriage market model, matching is positively assortative if types are complements: i.e. match output is supermodular. We reprise this famous result assuming time-intensive partner search and transferable output. We prove existence of a search equilibrium with a continuum of types, and then characterize matching. After showing that Becker's conditions no longer suffice for assortative matching, we find sufficient conditions valid for any search frictions and type distribution: supermodularity not only of match output, but also of its marginal product and cross partial derivative. Symmetric submodularity conditions imply negatively assortative matching. Examples show these conditions are necessary.
