UPDATE 1-Sirius XM Radio offers $250 mln notes to repay debt

* Sirius to offer $250 mln in senior secured notes

* Net proceeds to repay Liberty Media Corp

SAN FRANCISCO Aug 12 (Reuters) - Sirius XM Radio Inc (SIRI.O) on Thursday said it would offer $250 million in senior secured notes with net proceeds going to repay some of its debt obligations to Liberty Media Corp (LINTA.O).

The notes, which will come due in 2015, will be offered to qualified institutional buyers to repay certain debt under its credit agreement with Liberty Media Corp.

Earlier this year Sirius secured millions in financing from John Malone's Liberty Media Corp, which owns TV home shopping network QVC.

Pay-radio operator Sirius, which hosts programs by Howard Stern and Oprah Winfrey as well as Major League Baseball, reported a second quarter loss last week due to debt-related charges and a floundering auto industry.

Shares in New York-based Sirius closed up 2.64 percent at 51 cents on the Nasdaq and were flat after-hours. (Reporting by Clare Baldwin; Editing by Carol Bishopric)