Complementarities between consumer packaged goods (CPG) categories and correlated preferences driven by umbrella branding can create complex dependencies in consumer demand, wherein they both present as coincident purchases in the data, but have significantly different implications for retail pricing decisions. Only complementarity generates additional utility from joint consumption through increased compensated demand, leading to different optimal prices from optimizing product-line profits relative to those derived from isolated or within-category pricing models. We empirically assess whether complementary product offerings by the same brand are priced optimally across stores in the context of ready-to-bake cake mix and ready-to-eat frosting. Reduced-form evidence on purchase incidence and cross-price elasticities using aggregated data suggests that consumers prefer to choose the same brand for cross-category purchases and might purchase multiple units in the same shopping trip. However, these results cannot distinguish between the relative impacts of product-pair complementarities and correlated preferences. To separately identify complementarities, we employ a multiple discrete-continuous demand model that is both flexible and globally regular — two critical requirements for conducting pricing counterfactuals after estimating preference parameters. By integrating key purchase patterns (incidence, brand choice, quantity selection, and complementarity), we estimate cross-category complementary effects both within and across brands, demonstrating that these are distinctly identifiable from correlated preferences. Our results show that both mechanisms are relevant for pricing, with some brands exhibiting powerful correlated preferences and complementarities. We use these estimates along with wholesale price data to compute the optimal price margins and compare them to the observed margins from the retail scanner data. Our implied margins are lower than the average margins derived from data, which means that retailers can further reduce margins in these categories to drive up overall profits. These categories serve as loss leaders for those customers with strong preferences for some brands or categories in this space, prompting them to spend more in other categories in the store as well.