XM Satellite Radio Holdings Inc. C123456789 000004 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext MR A SAMPLE DESIGNATION (IF ANY) 000000000.000000 ext 000000000.000000 ext ADD 1 Electronic Voting Instructions ADD 2 ADD 3 You can vote by Internet or telephone! ADD 4 Available 24 hours a day, 7 days a week! ADD 5 Instead of mailing your proxy, you may choose one of the two voting ADD 6 methods outlined below to vote your proxy. VALIDATION DETAILS ARE LOCATED BELOW IN THE TITLE BAR. Proxies submitted by the Internet or telephone must be received by 1:00 a.m., Central Time, on Vote by Internet • Log on to the Internet and go to www.investorvote.com · Follow the steps outlined on the secured website. Vote by telephone • Call toll free 1-800-652-VOTE (8683) within the United States, Canada & Puerto Rico any time on a touch tone telephone. There is NO CHARGE to you for the call. Using a black ink pen, mark your votes with an X as shown in            X • Follow the instructions provided by the recorded message. this example. Please do not write outside the designated areas. Special Meeting Proxy Card 123456 C0123456789 12345 3 IF YOU HAVE NOT VOTED VIA THE INTERNET OR TELEPHONE, FOLD ALONG THE PERFORATION, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. 3 A Proposals — The Board of Directors recommends a vote FOR Proposal 1 and a vote FOR Proposal 2. For Against Abstain            For Against Abstain 1. Adopt the Agreement and Plan of Merger, dated as of 2. Approve any motion to adjourn or postpone the special February 19, 2007, by and among Sirius Satellite Radio Inc., meeting to a later date or dates, if necessary, to solicit Vernon Merger Corporation and XM Satellite Radio Holdings Inc. additional proxies if there are insufficient votes at the time of the special meeting to approve the proposal to adopt the 3. In their discretion, the proxies are authorized to vote upon any other Agreement and Plan of Merger. business that may properly come before the meeting. B Non-Voting Items Change of Address — Please print new address below. C Authorized Signatures — This section must be completed for your vote to be counted. — Date and Sign Below Please sign exactly as name(s) appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, corporate officer, trustee, guardian, or custodian, please give full title. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. C 1234567890 MR A SAMPLE (THIS AREA IS SET UP TO ACCOMMODATE 140 CHARACTERS) MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND + <STOCK#> 00S9UC.

 

3 IF YOU HAVE NOT VOTED VIA THE INTERNET OR TELEPHONE, FOLD ALONG THE PERFORATION, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. 3 Proxy — XM Satellite Radio Holdings Inc. 1500 Essington Place, N.E. Washington, DC 20002 SOLICITED BY THE BOARD OF DIRECTORS FOR THE SPECIAL MEETING OF STOCKHOLDERS The undersigned hereby appoints Joseph Title Baum and Nathaniel Davis, each with the power to appoint his substitute, and hereby authorizes them to represent and to vote, as designated on the reverse side, all shares of common stock of XM Satellite Radio Holdings Inc. held of record by the undersigned on at the Special Meeting of Stockholders to be held on and any adjournments thereof. THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED AS DIRECTED. IF NO DIRECTION IS GIVEN WITH RESPECT TO A PARTICULAR PROPOSAL, THIS PROXY WILL BE VOTED FOR SUCH PROPOSAL. PLEASE MARK, DATE, SIGN, AND RETURN THIS PROXY CARD PROMPTLY, USING THE ENCLOSED ENVELOPE. NO POSTAGE IS REQUIRED IF MAILED IN THE UNITED STATES. SEE REVERSE SIDE CONTINUED AND TO BE VOTED ON REVERSE SIDE. SEE REVERSE SIDE