FILED PURSUANT TO RULE 425

Filed by Sirius Satellite Radio Inc.
Pursuant to Rule 425 under the
Securities Act of 1933 and deemed filed
pursuant to Rule 14a-6 under the
Securities Exchange Act of 1934

Subject Company: XM Satellite Radio Holdings Inc.
Commission File No.: 0-27441

This communication 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 stockholders 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, 2006 and Quarterly Reports on Form 10-Q for the quarters ended March 31, 2007, June 30, 2007 and September 30, 2007, which are filed with the Securities and Exchange Commission (the “SEC”) and available at the SEC’s Internet site (http://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 communication.

Important Additional Information and Where to Find It

This communication is being made in respect of the proposed business combination involving SIRIUS and XM. In connection with the proposed transaction, SIRIUS has filed with the SEC a Registration Statement on Form S-4 containing a definitive Joint Proxy Statement/Prospectus and each of SIRIUS and XM may file with the SEC other documents regarding the proposed transaction. The Joint Proxy Statement/Prospectus was first mailed to stockholders of SIRIUS and XM on or about October 9, 2007. INVESTORS AND SECURITY HOLDERS OF SIRIUS AND XM ARE URGED TO READ THE JOINT PROXY

STATEMENT/PROSPECTUS, AS WELL AS 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 can obtain free copies of the Registration Statement and the Joint Proxy Statement/Prospectus 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 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, 36^th Floor, New York, NY 10020, Attention: Investor Relations or by directing a request to XM Satellite Radio Holdings Inc., 1500 Eckington Place, N.E. 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, 2006, which was filed with the SEC on March 1, 2007, and its proxy statement for its 2007 annual meeting of stockholders, which was filed with the SEC on April 23, 2007, 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, 2006, which was filed with the SEC on March 1, 2007 and its proxy statement for its 2007 annual meeting of stockholders, which was filed with the SEC on April 17, 2007. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, is contained in the Joint Proxy Statement/Prospectus filed with the SEC.

***

The following is a press release issued on November 13, 2007.

FORMER FCC CHAIRMAN HUNDT COMMENTS
ON SIRIUS-XM MERGER IN INTERVIEW

Architect of Satellite Radio at FCC Says Merger is Pro-Competitive,
1997 License Rules Not an Issue with the Merger

WASHINGTON, DC and NEW YORK, NY — November 13, 2007 — XM Satellite Radio (NASDAQ: XMSR) and SIRIUS Satellite Radio (NASDAQ: SIRI) announced today that, as part of an interview, former FCC Chairman Reed Hundt voiced support for the merger of SIRIUS and XM. A copy of the unedited transcript of the interview was filed today with the Federal Communications Commission (FCC).

Mr. Hundt served as Chairman of the FCC from 1993 through 1997. During his tenure, the Commission formulated rules for satellite radio and granted SIRIUS and XM their licenses, a process in which Mr. Hundt was integrally involved.

In the interview, Mr. Hundt discussed, among other things, the proposed merger of SIRIUS and XM, the creation of the satellite radio rules, the rationale behind the establishment of two satellite radio licenses and developments in the audio entertainment market since 1997.

The Merger is Pro-Competitive

When asked in an on the record conversation what his views of the merger were, Mr. Hundt stated:

“I think that if XM and Sirius combined, it will be pro-competitive in all likelihood. It seems to me that that is far more likely than not. It seems to me that what has happened over time is that these two firms have proved when kept apart to be incapable of mounting the really serious competition against ... terrestrial radio that I had always hoped for. And it seems to me that there’s no indication of any anticompetitive outcome if they do combine, so let’s give them a chance to have a sharper point on the arrow and see if they can do better in terms of penetrating the listener audience.”

Separate Licenses Are Not an Issue for the Merger

Given some of the outstanding questions surrounding the creation of two separate licenses for XM and SIRIUS at the time of inception, Mr. Hundt, as the Chair of the FCC at the time, used this discussion to clarify for the record the intention behind the FCC’s 1997 order creating the satellite radio service.

“I should just say my thought was this: Let’s start out with these two licenses, since it is not clear exactly what is the optimal business model, and then let’s let the two firms go at it for a while and see what happens. But it was never the case that these service rules were intended to be written [in] concrete or, like the Constitution of the United States, changed only through an elaborate process. It was an attempt to figure out a good way to get the satellite radio industry off to a pro-competitive start and then in the fullness of time the FCC and the parties and the people in the industry would be able to see, well, what works and what doesn’t work, what’s happening and what isn’t happening.”

The Market Has Changed

As the regulatory process continues and both the FCC and the Department of Justice (DoJ) review market definition, Mr. Hundt’s thoughts on the current market for audio entertainment and all of the competitive options available are especially interesting.

“[T]here are so many new ways fundamentally spawned from digitization and the tremendous increase of processing power per dollar, there are so many new ways to generate and deliver content to listeners that the idea that either satellite radio as a distinct market or that satellite radio is the only competitor against terrestrial broadcasting, neither one of those ideas holds water anymore.”

Satellite Radio Is a Necessary Competitor to AM/FM Radio

Mr. Hundt also reviewed the intention behind establishing satellite radio as a competitor to terrestrial AM/FM radio.

“[T]here was not a shadow of doubt in my mind that the competitive force of satellite radio was one of the very few arrows we had to shoot at this elephant-like industry that was going to be created in terrestrial radio. And as I said, looking back over the last ten years, both things proved to be true. It’s just that the arrow, if you want to put it that way, of satellite radio has not had a sharp enough point on it.”

As part of the interview, Mr. Hundt stated that, as former Chairman of the FCC, he felt an obligation to address on the record the important issues related to satellite radio with which he was integrally involved during his tenure.

For more information on the SIRIUS-XM merger, please visit www.xmmerger.com or www.siriusmerger.com.

# # #

About SIRIUS

SIRIUS, “The Best Radio on Radio,” delivers more than 130 channels of the best programming in all of radio. SIRIUS is the original and only home of 100% commercial free music channels in satellite radio, offering 69 music channels. SIRIUS also delivers 65 channels of sports, news, talk, entertainment, traffic, weather and data. SIRIUS is the Official Satellite Radio Partner of the NFL, NASCAR and NBA, and broadcasts live play-by-play games of the NFL and NBA, as well as live NASCAR races. All SIRIUS programming is available for a monthly subscription fee of only $12.95.

SIRIUS Internet Radio (SIR) is a CD-quality, Internet-only version of the SIRIUS radio service, without the use of a radio, for the monthly subscription fee of $12.95. SIR delivers more than 80 channels of talk, entertainment, sports, and 100% commercial free music.

SIRIUS Backseat TV™ is the first ever live in-vehicle rear seat entertainment featuring three channels of children’s TV programming, including Nickelodeon, Disney Channel and Cartoon Network, for the subscription fee of $6.99 plus applicable audio subscription fee.

SIRIUS products for the car, truck, home, RV and boat are available in more than 20,000 retail locations, including Best Buy, Circuit City, Crutchfield, Costco, Target, Wal-Mart, Sam’s Club, RadioShack and at shop.sirius.com.

SIRIUS radios are offered in vehicles from Audi, Bentley, BMW, Chrysler, Dodge, Ford, Infiniti, Jaguar, Jeep^®, Land Rover, Lexus, Lincoln, Mercury, Maybach, Mazda, Mercedes-Benz, MINI, Mitsubishi, Nissan, Rolls Royce, Scion, Toyota, Volkswagen, and Volvo. Hertz also offers SIRIUS in its rental cars at major locations around the country.

Click on www.sirius.com to listen to SIRIUS live, or to purchase a SIRIUS radio and subscription.

About XM

XM is America’s number one satellite radio company with more than 8.5 million subscribers. Broadcasting live daily from studios in Washington, DC, New York City, Chicago, the Country Music Hall of Fame in Nashville, Toronto and Montreal, XM’s 2007 lineup includes more than 170 digital channels of choice from coast to coast: commercial-free music, premier sports, news, talk radio, comedy, children’s and entertainment programming; and the most advanced traffic and weather information.

XM, the leader in satellite-delivered entertainment and data services for the automobile market through partnerships with General Motors, Honda, Hyundai, Nissan, Porsche, Subaru, Suzuki and Toyota is available in 140 different vehicle models for 2007. XM’s industry-leading products are available at consumer electronics retailers nationwide. For more information about XM hardware, programming and partnerships, please visit http://www.xmradio.com.

###

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 stockholders 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, 2006, and Quarterly Reports on Form 10-Q for the quarters ended March 31, 2007, June 30, 2007 and September 30, 2007,

which are filed with the Securities and Exchange Commission (the “SEC”) and available at the SEC’s Internet site (http://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 communication.

Important Additional Information and Where to Find It

This communication is being made in respect of the proposed business combination involving SIRIUS and XM. In connection with the proposed transaction, SIRIUS has filed with the SEC a Registration Statement on Form S-4 containing a definitive Joint Proxy Statement/Prospectus and each of SIRIUS and XM may file with the SEC other documents regarding the proposed transaction. The Joint Proxy Statement/Prospectus was first mailed to stockholders of SIRIUS and XM on or about October 9, 2007. INVESTORS AND SECURITY HOLDERS OF SIRIUS AND XM ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS, AS WELL AS OTHER DOCUMENTS FILED WITH THE SEC CAREFULLY IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

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, 2006, which was filed with the SEC on March 1, 2007, and its proxy statement for its 2007 annual meeting of stockholders, which was filed with the SEC on April 23, 2007, 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, 2006, which was filed with the SEC on March 1, 2007 and its proxy statement for its 2007 annual meeting of stockholders, which was filed with the SEC on April 17, 2007. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, is contained in the Joint Proxy Statement/Prospectus filed with the SEC.

###

SIRIUS
Media Relations
Patrick Reilly
212-901-6646
PReilly@siriusradio.com

Kelly Sullivan
Joele Frank, Wilkinson Brimmer Katcher
212-355-4449
ksullivan@joelefrank.com