As a subsidiary of Xcel Energy, Public Service Co. of Colorado's corporate credit rating reflects both the more stable business profile and stronger financial profile of the regulated utility subsidiaries and the more volatile earnings and much weaker financial profile of the non-regulated subsidiary, NRG Energy Inc. The 'high average' business profile (4) of utility subsidiaries Northern States Power Minnesota, Northern States Power Wisconsin, Public Service Co. of Colorado and Southwestern Public Service Company, is characterized by regional and economic diversity; average to strong customer growth; and regulators that support reasonable rates of return, timely cost recovery, and incentives to maintain and improve operating efficiency. In contrast, the 'below average' business profile (9) of NRG Energy is characterized by a