Sure, supermarket might carry hundreds of types of wines, but a recent study reveals that the wine industry is actually quite concentrated to the point where a mere three firms account for half of US wine sales. Michigan State professor Philip Howard has posted the results of his study of the inventory of 20 Michigan wine retailers, where his team "recorded more than 3,600 unique varieties of wine, and traced their relationships with more than 1,000 different firms."
While that sure is a whole lot of wine, it seems many of these firms can be traced back to parent companies such as E&J Gallo Winery (Carlo Rossi, Barefoot Cellars, etc), The Wine Group (Franzia, Almaden, etc) and Constellation Brands (Woodbridge, Arbor Mist, etc), which altogether control 51.5 percent of US wine sales. As Howard writes, "The top firms each contribute to an illusion of diverse ownership by offering dozens of brands (and hundreds of varieties), many of which do not clearly indicate the parent company on their label."
Howard admits that the beer and soda markets are even more concentrated, noting that "two firms control approximately three-quarters of all sales" for those industries in the US. But, he writes, the wine industry is becoming more concentrated each year as acquisitions and mergers continue.