A category killer is a retailer, often a big-box store, that specializes in and carries a large product assortment of a given category. Through their wide merchandise selections, low pricing, deep supply, large buying power, and market penetration, they have a comparative advantage over other, smaller retailers, and can greatly reduce the sales of rival retailers within that category, in the area and beyond it. In essence, they are a price- or discount-based specialist mass-retailer. Chains such as OfficeMax, Best Buy, Barnes & Noble, and Hobby Lobby have been considered category killers. Once typically found in power centers, increasingly they are found in or adjacent to (as an outbuilding of) repurposed traditional malls. Large category killer stores are mostly in mid- and large-sized cities, because a large population is required to be feasible.

Impact

Local merchants in cities with category killers "may suffer a substantial reduction in sales," and stores in a wider radius can be affected by the draw. Between 1983 and 1993, Iowans spent 31% less in hardware stores, translating to a loss of 37% in the same time to those stores as a result of category killer stores.

Canadian retailers

United States retailers

Sporting goods stores that are category killers range in footprint from 10000 to 40000 sqft. Home Depot carries 30,000 items in 100000 sqft stores.