content: UNITED STATES                          OMB APPROVAL
                 SECURITIES AND EXCHANGE COMMISSION
                       Washington, D.C. 20549           OMB Number:   3235-0101
                                                        Expires:August 31, 2003
                            FORM 144                    Estimated average burden
                                                        hours per response.....2.0
  
           NOTICE OF PROPOSED SALE OF SECURITIES              SEC USE ONLY
  PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933     Document Sequence No.
  
  ATTENTION:  Transmit for filing 3 copies of this form     Cusip Number
              with either placing an order with a broker
              to execute sale or executing a sale           Work Location
              directly with a market maker
  <TABLE>
  <CAPTION>
  <S>                                               <C>                     <C>                          <C>
  -----------------------------------------------------------------------------------------------------------------------------------
  ||1(a) Name of Issuer                            |(b)IRS Ident. No.       |(c) S.E.C. File No.        |
  |                                                |                        |                           |
  |      XM SATELLITE RADIO HOLDINGS, INC.         |   54-1878819           |    005-57011              |
  |                                                |                        |                           |
  -----------------------------------------------------------------------------------------------------------------------------------
  |(d) Address of Issuer               Street                   City                State      Zip Code | (e) Telephone No.          |
  |                                                                                                     |----------------------------
  |                                                                                                     | Area Code|   Number        |
  |                     1500 Eckington Place, NE              Washington             DC      20002-2194 |   202    |  380-4000       |
  |---------------------------------------|------------------------------------------------------------------------------------------
  |2(a) Name of Person for whose account the |(b) IRS Ident. No.   |(c) Relationship to |(d) Address Street    City    State Zip Code|
  |     Securities are to be sold            |                     |    Issuer          |                                            |
  |                                          |                     |                    |                                            |
  |     BARON iOPPORTUNITY FUND              |    13-4083689       |    NONE            |    767 Fifth Avenue, New York, NY 10153    |
  -----------------------------------------------------------------------------------------------------------------------------------
  INSTRUCTION:The person filing this notice should contact the issuer to obtain the IRS Identification Number and the SEC file Number
  -----------------------------------------------------------------------------------------------------------------------------------
  |3(a)             |(b)                             |SEC USE ONLY|(c)           |(d)          |(e)         |(f)         |(g)        |
  |    Title of the |   Name and Address of Each     |------------| Number of    |  Aggregate  | Number of  | Approximate|Name of    |
  |    Class of     |   Broker Through Whom the      | Broker-    | Shares or    |   Market    | Shares or  |  Date of   |Each       |
  |    Securities   |   Securities are to be Offered | Dealer File| Other Units  |    Value    | Other Units|     Sale   |Securities |
  |    To Be Sold   |   or Each Market Maker who is  | Number     | to be Sold   |             | Outstanding|            |Exchange   |
  |                 |   Acquiring the Securities     |            |              |             |            |            |           |
  -----------------------------------------------------------------------------------------------------------------------------------
  |                 |   Lehman Brothers              |            |              |             |            | Over the   |           |
  |   Class A       |   280 Park Avenue              |            |              |             |            | next 90    | NASDAQ    |
  |   Common        |   New York, NY 10017           |            |  42,514      |  $ 701,481  | 74,449,133 | days.      |           |
  ------------------------------------------------------------------------------------------------------------------------------------
  |                 |   Solomon Smith Barney, Inc.   |            |              |             |            |            |           |
  |                 |   390 Greenwich Street         |            |              |             |            |            |           |
  |                 |   New York, NY 10013           |            |              |             |            |            |           |
  ------------------------------------------------------------------------------------------------------------------------------------
  |                 |   Bear Sterns & Co., Inc.      |            |              |             |            |            |           |
  |                 |   383 Madison Avenue           |            |              |             |            |            |           |
  |                 |   New York, NY 10179           |            |              |             |            |            |           |
  ------------------------------------------------------------------------------------------------------------------------------------
  </TABLE>
  
  
  
  
  
  
  <PAGE>
                         TABLE I  - SECURITIES TO BE SOLD
     Furnish the following information with respect to the acquisition of the
     securities to be sold and with respect to the payment of all or any part
     of the purchase price or other consideration therefor:
  <TABLE>
  <CAPTION>
  <S>         <C>       <C>                                 <C>                                 <C>                  <C>      <C>
  -----------------------------------------------------------------------------------------------------------------------------------
  |Title of  |Date you |                                   | Name of Person from Whom Acquired |     Amount of      |Date of |Nature |
  |the Class |Acquired | Nature of Acquisition Transaction |                                   |Securities Acquired |Payment |of     |
  |          |         |                                   |                                   |                    |        |Payment|
  |----------|---------|-----------------------------------|-----------------------------------|--------------------|--------|-------|
  | Common   | 08/00   | Conversion from Series C          |        Issuer                     |    42,514 in       | 8/8/00 | Cash  |
  |          |(convert-| Convertible Preferred             |                                   |    conversion      |        |       |
  |          | ed into |                                   |                                   |                    |        |       |
  |          | Common  |                                   |                                   |                    |        |       |
  |          | 01/02)  |                                   |                                   |                    |        |       |
  |          |         |                                   |                                   |                    |        |       |
  |          |         |                                   |                                   |                    |        |       |
  |          |         |                                   |                                   |                    |        |       |
  -----------------------------------------------------------------------------------------------------------------------------------|
  </TABLE>
  
  
  ===============================================================================
  
                 TABLE II - SECURITIES SOLD DURING THE PAST 3 MONTHS
  Furnish the following information as to all securities of the issuer sold during
  the past 3 months by the person for whose account the securities are to be sold.
  
  <TABLE>
  <CAPTION>
  <S>         <C>       <C>                                 <C>                                 <C>                  <C>      <C>
  -----------------------------------------------------------------------------------------------------------------------------------
  |                                                        |                                 |             |    Amount of   |Gross   |
  |             Name and Address of Seller                 |      Title of Securities Sold   | Date of Sale| Securities Sold|Proceeds|
  |----------------------------------------------------------------------------------------------------------------------------------|
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  -----------------------------------------------------------------------------------------------------------------------------------|
  </TABLE>
  REMARKS:
  
  
  
                      ATTENTION:
                      The person for whose  account the  securities  to which this
                      notice  relates are to be sold hereby  represents by signing
                      this  notice  that he does  not  know any  material  adverse
                      information  in  regard  to  the  current  and   prospective
                      operations of the Issuer of the  securities to be sold which
                      has not been publicly disclosed.
  
                      BARON ASSET FUND on behalf of the
                      BARON iOPPORTUNITY FUND series
                      By:
  
  
    01/07/02          /s/ Ronald Baron
  ----------------    ----------------------------------
  Date of Notice          Ronald Baron, Chairman & CEO
metadata_documents: [{"type": "144", "sequence": "1", "filename": "formbio144.txt", "description": "FORM 144 - BIO", "secsgml_size_bytes": 11011}]
text: UNITED STATES                          OMB APPROVAL
                 SECURITIES AND EXCHANGE COMMISSION
                       Washington, D.C. 20549           OMB Number:   3235-0101
                                                        Expires:August 31, 2003
                            FORM 144                    Estimated average burden
                                                        hours per response.....2.0
  
           NOTICE OF PROPOSED SALE OF SECURITIES              SEC USE ONLY
  PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933     Document Sequence No.
  
  ATTENTION:  Transmit for filing 3 copies of this form     Cusip Number
              with either placing an order with a broker
              to execute sale or executing a sale           Work Location
              directly with a market maker
  -----------------------------------------------------------------------------------------------------------------------------------
  ||1(a) Name of Issuer                            |(b)IRS Ident. No.       |(c) S.E.C. File No.        |
  |                                                |                        |                           |
  |      XM SATELLITE RADIO HOLDINGS, INC.         |   54-1878819           |    005-57011              |
  |                                                |                        |                           |
  -----------------------------------------------------------------------------------------------------------------------------------
  |(d) Address of Issuer               Street                   City                State      Zip Code | (e) Telephone No.          |
  |                                                                                                     |----------------------------
  |                                                                                                     | Area Code|   Number        |
  |                     1500 Eckington Place, NE              Washington             DC      20002-2194 |   202    |  380-4000       |
  |---------------------------------------|------------------------------------------------------------------------------------------
  |2(a) Name of Person for whose account the |(b) IRS Ident. No.   |(c) Relationship to |(d) Address Street    City    State Zip Code|
  |     Securities are to be sold            |                     |    Issuer          |                                            |
  |                                          |                     |                    |                                            |
  |     BARON iOPPORTUNITY FUND              |    13-4083689       |    NONE            |    767 Fifth Avenue, New York, NY 10153    |
  -----------------------------------------------------------------------------------------------------------------------------------
  INSTRUCTION:The person filing this notice should contact the issuer to obtain the IRS Identification Number and the SEC file Number
  -----------------------------------------------------------------------------------------------------------------------------------
  |3(a)             |(b)                             |SEC USE ONLY|(c)           |(d)          |(e)         |(f)         |(g)        |
  |    Title of the |   Name and Address of Each     |------------| Number of    |  Aggregate  | Number of  | Approximate|Name of    |
  |    Class of     |   Broker Through Whom the      | Broker-    | Shares or    |   Market    | Shares or  |  Date of   |Each       |
  |    Securities   |   Securities are to be Offered | Dealer File| Other Units  |    Value    | Other Units|     Sale   |Securities |
  |    To Be Sold   |   or Each Market Maker who is  | Number     | to be Sold   |             | Outstanding|            |Exchange   |
  |                 |   Acquiring the Securities     |            |              |             |            |            |           |
  -----------------------------------------------------------------------------------------------------------------------------------
  |                 |   Lehman Brothers              |            |              |             |            | Over the   |           |
  |   Class A       |   280 Park Avenue              |            |              |             |            | next 90    | NASDAQ    |
  |   Common        |   New York, NY 10017           |            |  42,514      |  $ 701,481  | 74,449,133 | days.      |           |
  ------------------------------------------------------------------------------------------------------------------------------------
  |                 |   Solomon Smith Barney, Inc.   |            |              |             |            |            |           |
  |                 |   390 Greenwich Street         |            |              |             |            |            |           |
  |                 |   New York, NY 10013           |            |              |             |            |            |           |
  ------------------------------------------------------------------------------------------------------------------------------------
  |                 |   Bear Sterns & Co., Inc.      |            |              |             |            |            |           |
  |                 |   383 Madison Avenue           |            |              |             |            |            |           |
  |                 |   New York, NY 10179           |            |              |             |            |            |           |
  ------------------------------------------------------------------------------------------------------------------------------------
  TABLE I  - SECURITIES TO BE SOLD
     Furnish the following information with respect to the acquisition of the
     securities to be sold and with respect to the payment of all or any part
     of the purchase price or other consideration therefor:
  -----------------------------------------------------------------------------------------------------------------------------------
  |Title of  |Date you |                                   | Name of Person from Whom Acquired |     Amount of      |Date of |Nature |
  |the Class |Acquired | Nature of Acquisition Transaction |                                   |Securities Acquired |Payment |of     |
  |          |         |                                   |                                   |                    |        |Payment|
  |----------|---------|-----------------------------------|-----------------------------------|--------------------|--------|-------|
  | Common   | 08/00   | Conversion from Series C          |        Issuer                     |    42,514 in       | 8/8/00 | Cash  |
  |          |(convert-| Convertible Preferred             |                                   |    conversion      |        |       |
  |          | ed into |                                   |                                   |                    |        |       |
  |          | Common  |                                   |                                   |                    |        |       |
  |          | 01/02)  |                                   |                                   |                    |        |       |
  |          |         |                                   |                                   |                    |        |       |
  |          |         |                                   |                                   |                    |        |       |
  |          |         |                                   |                                   |                    |        |       |
  -----------------------------------------------------------------------------------------------------------------------------------|
  ===============================================================================
  
                 TABLE II - SECURITIES SOLD DURING THE PAST 3 MONTHS
  Furnish the following information as to all securities of the issuer sold during
  the past 3 months by the person for whose account the securities are to be sold.
  -----------------------------------------------------------------------------------------------------------------------------------
  |                                                        |                                 |             |    Amount of   |Gross   |
  |             Name and Address of Seller                 |      Title of Securities Sold   | Date of Sale| Securities Sold|Proceeds|
  |----------------------------------------------------------------------------------------------------------------------------------|
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  |                                                        |                                 |             |                |        |
  -----------------------------------------------------------------------------------------------------------------------------------|
  REMARKS:
  
                      ATTENTION:
                      The person for whose  account the  securities  to which this
                      notice  relates are to be sold hereby  represents by signing
                      this  notice  that he does  not  know any  material  adverse
                      information  in  regard  to  the  current  and   prospective
                      operations of the Issuer of the  securities to be sold which
                      has not been publicly disclosed.
  
                      BARON ASSET FUND on behalf of the
                      BARON iOPPORTUNITY FUND series
                      By:
  
    01/07/02          /s/ Ronald Baron
  ----------------    ----------------------------------
  Date of Notice          Ronald Baron, Chairman & CEO