Description MXenergy strives to deliver maximum energy for minimum cost. Providing natural gas and electricity to more than 500,000 customers in deregulated markets in 15 US states and British Columbia and Ontario, the company differentiates itself by offering a set rate plan that doesn't fluctuate with changing energy prices in addition to traditional variable rate plans. Serving residential and small business customers in more than 40 utility territories (billing is done through local utility companies), MXenergy has offices in Connecticut, Maryland, and Texas. In 2011 the company was acquired by Constellation Energy for $175 million.