February 20, 2007


Dear XM Radio Subscriber:

We want to share with you some exciting news: Yesterday, in Washington
DC, we announced XM Radio will be merging with Sirius Satellite Radio
to form the premier digital audio service.

The merger will create a satellite radio company that will provide
consumers across the country with more and better premium radio
programming. The combined company will be able to compete better in what has
become a very complex and dynamic entertainment market.

Where today our exclusive contracts mean you had to choose between
baseball and football or Oprah and Martha Stewart, the new company will
seek to ensure that in the future, you will be able to access both
companies' programming. And, once we are fully integrated, those of you who
have factory-installed satellite radio will no longer be limited to the
programming provided by the exclusive satellite radio service chosen by
their car manufacturer.

This merger should be completed in late 2007 or early in 2008.
Throughout the year, we will provide updates on how the merger is progressing
and information will be available at our website, www.xmradio.com.

Between today and the merger date, as well as during the period
immediately after the merger date, all of your services will remain the same.
The channel lineup, the customer service number, the great music
technology, and the XM Radio web site will all remain unchanged and there
will be no disruption to service. But, if you have questions, information
will be available and maintained on our website, and you can contact
our Listener Care team at 800-XMRADIO, with questions and concerns.

XM Radio continues to be committed to providing you the highest quality
audio entertainment and customer service available today. After the
merger, our new company will be able to offer you the most exciting
listening experience in radio.

Sincerely,

Hugh Panero
CEO, XM Satellite Radio


Forward Looking Statements
This letter contains "forward-looking statements" within the meaning of
the Private Securities Litigation Reform Act of 1995. Such statements
include, but are not limited to, statements about the benefits of the
business combination transaction involving Sirius Satellite Radio Inc.
and XM Satellite Radio Holdings Inc., including potential synergies and
cost savings and the timing thereof, future financial and operating
results, the combined company's plans, objectives, expectations and
intentions with respect to future operations, products and services; and
other statements identified by words such as "anticipate," "believe,"
"plan," "estimate," "expect," "intend," "will," "should," "may," or words of
similar meaning. Such forward-looking statements are based upon the
current beliefs and expectations of SIRIUS' and XM's management and are
inherently subject to significant business, economic and competitive
uncertainties and contingencies, many of which are difficult to predict
and generally beyond the control of SIRIUS and XM. Actual results may
differ materially from the results anticipated in these forward-looking
statements.

The following factors, among others, could cause actual results to
differ materially from the anticipated results or other expectations
expressed in the forward-looking statement: general business and economic
conditions; the performance of financial markets and interest rates; the
ability to obtain governmental approvals of the transaction on a timely
basis; the failure of SIRIUS and XM shareholders to approve the
transaction; the failure to realize synergies and cost-savings from the
transaction or delay in realization thereof; the businesses of SIRIUS and XM
may not be combined successfully, or such combination may take longer,
be more difficult, time-consuming or costly to accomplish than
expected; and operating costs and business disruption following the merger,
including adverse effects on employee retention and on our business
relationships with third parties, including manufacturers of radios,
retailers, automakers and programming providers. Additional factors that could
cause SIRIUS' and XM's results to differ materially from those
described in the forward-looking statements can be found in SIRIUS' and XM's
Annual Reports on Form 10-K for the year ended December 31, 2005, and
Quarterly Reports on Form 10-Q for the quarters ended March 31, 2006, June
30, 2006 and September 30, 2006 which are filed with the Securities and
Exchange Commission (the "SEC") and available at the SEC's Internet
site www.sec.gov The information set forth herein speaks only as of the
date hereof, and Sirius and XM disclaim any intention or obligation to
update any forward looking statements as a result of developments
occurring after the date of this press release.

Important Additional Information Will be Filed with the SEC This
communication is being made in respect of the proposed business combination
involving SIRIUS and XM. In connection with the proposed transaction,
SIRIUS plans to file with the SEC a Registration Statement on Form S-4
containing a Joint Proxy Statement/Prospectus and each of SIRIUS and XM
plan to file with the SEC other documents regarding the proposed
transaction. The definitive Joint Proxy Statement/Prospectus will be mailed
to stockholders of SIRIUS and XM. INVESTORS AND SECURITY HOLDERS OF
SIRIUS AND XM ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND
OTHER DOCUMENTS FILED WITH THE SEC CAREFULLY IN THEIR ENTIRETY WHEN THEY
BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT
THE PROPOSED TRANSACTION.

Investors and security holders will be able to obtain free copies of
the Registration Statement and the Joint Proxy Statement/Prospectus (when
available) and other documents filed with the SEC by SIRIUS and XM
through the web site maintained by the SEC at www.sec.gov. Free copies of
the Registration Statement and the Joint Proxy Statement/Prospectus
(when available) and other documents filed with the SEC can also be
obtained by directing a request to Sirius Satellite Radio Inc., 1221 Avenue of
the Americas, New York, NY 10020, Attention: Investor Relations or by
directing a request to XM Satellite Radio Holdings Inc., 1500 Eckington
Place, NE Washington, DC 20002, Attention: Investor Relations.

SIRIUS, XM and their respective directors and executive officers and
other persons may be deemed to be participants in the solicitation of
proxies in respect of the proposed transaction. Information regarding
SIRIUS' directors and executive officers is available in its Annual Report
on Form 10-K for the year ended December 31, 2005, which was filed with
the SEC on March 13, 2006, and its proxy statement for its 2006 annual
meeting of stockholders, which was filed with the SEC on April 21,
2006, and information regarding XM's directors and executive officers is
available in XM's Annual Report on Form 10-K, for the year ended December
31, 2005, which was filed with the SEC on March 3, 2006 and its proxy
statement for its 2006 annual meeting of shareholders, which was filed
with the SEC on April 25, 2006. Other information regarding the
participants in the proxy solicitation and a description of their direct and
indirect interests, by security holdings or otherwise, will be contained
in the Joint Proxy Statement/Prospectus and other relevant materials to
be filed with the SEC when they become available.

Please note: this is not a promotional e-mail. As an XM subscriber,
you will periodically receive service notices via e-mail. These service
notices are intended to provide you with helpful information that will
facilitate and enhance your XM listening experience.


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