Yankee Energy System, Inc. operates through wholly owned subsidiaries. The subsidiaries are Yankee Gas Services Company, Yankee Energy Financial Services Company, Yankee Energy Services Company, NorConn Properties, Inc. and R.M. Services, Inc. The company's subsidiary YESCo provides a wide range of energy-related services, YESCo controls division provides building automation with engineering, installation and maintenance of building control systems, YESCo mechanical services division provides comprehensive heating, ventilation and air-conditioning, boiler and refrigeration equipment services and installation. RMS provides consumer collection services for companies and Yankee Financial provides a full range of equipment and home improvement financing options. During the fiscal year 1999, the company entered into an agreement and plan of merger with Northeast Utilities. Natural gas distribution accounted for 90% of fiscal 1999 revenues and energy-related, consumer collection and financial services, 10%.