NSTAR was formed in 1999 by the merger of Commonwealth Energy System and BEC Energy.
In 2010 NSTAR merged with Northeast Utilities, with the new company retaining the Northeast Utilities name. The merger was completed in 2012.
Today NSTAR operates as a subsidiary of Northest Utilities.
NSTAR Electric and Gas transmits and distributes electricity to more than 1.1 million residential, industrial, and commercial customers in Massachusetts. The state has a deregulated power market and and competition is fierce, with NSTAR providing standard offer and default supply services to retail customers.
NSTAR also distributes natural gas to 300,000 customers, also in Massachusetts.
Northeast Utilities is a publicly traded Fortune 500 energy company with several subsidiaries offering electricity and natural gas to over 3.6 million customers.