The 'BB' corporate credit rating assigned to Tucson Electric Power (TEP) reflects the consolidated creditworthiness of UniSource Energy Corp. (UniSource). UniSource is not rated by Standard&Poor's Ratings Services. TEP serves nearly 390,000 electric customers within Tucson, and southeastern Arizona is UniSource's primary holding, generating about 88% of UniSource's cash flows from operations in 2005. Through an intermediate holding company, UniSource Energy Services Inc. (UES), UniSource also owns UNS Gas and UNS Electric that together provide retail natural gas and electric services to about 233,000 mostly residential customers in six counties located in northern and southern Arizona. (UNS Gas and UNS Electric are owned by UniSource through UES.) UniSource also owns unregulated energy and venture capital interests through Millennium
