ESCO): A company that offers to reduce a client's electricity consumption with the cost savings being split with the client. May also be called an Efficiency Services Company.

A company that is an alternate supplier of energy is called an ESCO. In energy deregulation, customers can purchase energy supply from an ESCO. In each area these ESCO's have to be licensed or approved by the state utility commission as well as the local utility company in whose territory they are working.

While initially applied to those firms performing energy efficiency upgrades, now (in some states) defined to include those who merely supply retail energy. Often abbreviated as ESCo or ESCO. See also ESCo.

A company which markets and provides energy-related products and services.