The commercial real estate sector is responsible for a large share of a city’s overall carbon footprint. An ongoing trend in this sector has been the entry of big-box stores such as Wal-Mart. Using a unique monthly panel data set for every Wal-Mart store in California from 2006 through 2011, we document three main findings about the environmental performance of big-box retailers. First, Wal-Mart’s stores exhibit very little store-to-store variation in electricity consumption relative to a control group of similar size and vintage retail stores. Second, Wal-Mart’s store’s electricity consumption is lower in higher priced utilities and is independent of the store’s ownership versus leased status. Third, unlike other commercial businesses, Wal-Mart’s newer buildings consume less electricity. Together, these results highlight the key roles that corporate size and centralization of management play in determining a key indicator of a firm’s overall environmental performance.