Sirius XM Radio (SIRI)

9.75% Senior Supplemental Indenture

On March 6, 2009, XM executed and delivered a Third Supplemental Indenture (the “XM 9.75% Notes Supplemental Indenture”), dated as of March 6, 2009, by and among XM, XM Holdings, XM Equipment Leasing LLC, XM Radio Inc. and The Bank of New York Mellon, as trustee, which supplements the indenture, dated as of May 1, 2006, among XM, XM Holdings, XM Equipment Leasing LLC and the trustee with respect to XM’s 9.75% Senior Notes due 2014 (the “9.75% Notes”).

The XM 9.75% Notes Supplemental Indenture was entered into in connection with XM’s previously announced tender offer and consent solicitation with respect to the XM 9.75% Notes commenced on July 29, 2008. As part of the offer, XM sought and received the requisite consents from holders of the XM 9.75% Notes to proposed amendments relating to the XM 9.75% Notes and the related indenture. The XM 9.75% Notes Supplemental Indenture contains the proposed amendments which amend the indenture to eliminate substantially all of the restrictive covenants contained in the indenture and the XM 9.75% Notes, eliminate certain events of default and modify or eliminate certain other provisions contained in the indenture and the XM 9.75% Notes.

Under the Indenture, dated as of July 31, 2008, among XM Escrow LLC and The Bank of New York Mellon, as trustee, relating to the 13% Senior Notes due 2014 (the “XM 13% Notes”), the maturity of the XM 13% Notes changes from August 1, 2014 to August 1, 2013 when certain conditions have been satisfied. Following the execution of the XM 9.75% Notes Supplemental Indenture, all of these conditions have been satisfied and the XM 13% Notes will mature on August 1, 2013.

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Table of Contents

SIRIUS XM RADIO INC. AND SUBSIDIARIES

9.75% Senior Supplemental Indenture