Eversource Energy is a publicly traded, Fortune 500 energy company headquartered in Hartford, Connecticut, and Boston, Massachusetts, with several regulated subsidiaries offering retail electricity, natural gas service and water service to approximately 4 million customers in Connecticut, Massachusetts, and New Hampshire. Following its 2012 merger with Boston-based NSTAR, Northeast Utilities had more than 4,270 circuit miles of electric transmission lines, 72,000 pole miles of distribution lines, and 6,459 miles of natural gas pipeline in New England. On February 2, 2015, the company and all its subsidiaries rebranded themselves as "Eversource Energy". The stock symbol changed on February 19, 2015, from "NU" to "ES". Wikipedia