NSTAR is a holding company. The Company, through its subsidiaries, is engaged in the energy delivery business. During the year ended December 31, 2011, the Company serves approximately 1.4 million customers in Massachusetts, including approximately 1.1 million electric distribution customers in 81 communities and approximately 300,000 natural gas distribution customers in 51 communities. During 2011, its utility operations accounted for approximately 99% of consolidated operating revenues. NSTAR�s utility operations derive their operating revenues primarily from electric and natural gas sales, distribution, and transmission services to customers. Its principal subsidiaries include NSTAR Electric Company (NSTAR Electric) and NSTAR Gas Company (NSTAR Gas).