Wine production in Germany has a tradition of more than 200 years in each of the 13 German quality wine-growing regions. Even today small grape growers dominate the industry. As a result, most of the viticulturists are members of cooperatives. Our observation that grape growers still turn to wine co-ops, and hence, the increase in co-op members and vineyards, might indicate that the wine co-ops are successful. Thus, the aim of our paper is two-fold. First, we analyze the structure of this complex sector and the managerial construct strategic member groups. Second, we empirically test whether the formation of strategic groups is a driver of cooperative success.