US companies should make energy efficiency the foundation of their commitment to addressing climate change because it can yield large reductions in greenhouse gas emissions while providing energy cost savings and other benefits. But while many companies have begun to report on how they are addressing climate and sustainability, the majority lack energy efficiency targets that can help drive investment. This brief reviews the opportunities for reducing corporate carbon emissions through energy savings and efficiency targets. An analysis of 30 corporate sustainability reports finds that all of them mention efficiency, but few deal with it throughout the value chain (in facilities and operations, transportation and distribution, supplier engagement, and product end-use). We examine the key role of energy savings in each of these areas, describe nascent efforts to include efficiency in financial disclosures, and conclude with recommendations for companies and investors.