Guarantees:

12 Months Ended

Dec. 31, 2011

Guarantees:

Guarantees:

10. Guarantees:

    As of December 31, 2011 and 2010, our guarantees included those disclosed in Note 5 for pollution control bonds assumed by Georgia Transmission in connection with a corporate restructuring and for rental payments due under the terms of the Rocky Mountain lease transactions and replacement credit enhancement. See Note 2 for discussion of Rocky Mountain lease transactions.

    In connection with our corporate restructuring in 1997, Georgia Transmission assumed 16.86% of the then outstanding indebtedness associated with pollution control bonds pursuant to an assumption agreement and an indemnity agreement. If Georgia Transmission fails to satisfy its obligation under this debt assumption, we remain liable for any unsatisfied amounts. In that event, we would be entitled to reimbursement from Georgia Transmission for any amounts we paid. At December 31, 2011, the total obligation assumed by Georgia Transmission related to outstanding pollution control bonds was $40,105,000.

    The amount of the fair value of our guarantee related to the pollution control bonds assumed by Georgia Transmission is immaterial due to the small amount of assumed principal outstanding and the high credit rating of Georgia Transmission. We estimate that the current maximum aggregate amount of exposure we would have if we were required to purchase the equity interests of the six owner trusts under the Rocky Mountain lease transactions is approximately $250,000,000. See Note 2 for discussion of Rocky Mountain lease transactions.