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; Large purchased power obligations; and Parent company debt increases debt service burden. The rating on Public Service Co. of Colorado (PSCo) is based on the consolidated credit profile of integrated electric and natural gas utility holding company Xcel Energy Inc. and its vertically integrated utility subsidiaries--PSCo, Northern States Power Co. (NSP-Minnesota), Northern States Power Wisconsin (NSP-Wisconsin), and Southwestern Public Service Co. (SPS). Minneapolis, Minn.-based Xcel had $8.3 billion of debt, including $400 million of junior subordinated notes, and $105 million of preferred stock as of March 31, 2008. Of these amounts, PSCo had $2.3
