Diversity of geography, fuel, and economy; Regulatory support; Plant operating efficiency; and Ongoing cost cutting. Aggressive capital spending program; High dependence on continuing supportive rate treatment; and Large purchased power obligations. The rating on integrated electric and natural gas utility holding company Xcel Energy Inc. is based on the consolidated credit profile of Xcel and its vertically integrated utility subsidiaries--Northern States Power Co. (NSP-Minnesota), Northern States Power Wisconsin (NSP-Wisconsin), Public Service Co. of Colorado (PSCo), and Southwestern Public Service Co. (SPS). Minneapolis, Minn.-based Xcel had $8.7 billion of debt, including $400 million of junior subordinated notes as of Sept. 30, 2008. Xcel, as a regulated utility holding company, serves 3.3 million electric and 1.8 million natural-gas customers in eight different