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                                                                  EXHIBIT 10.8


                           ASSIGNMENT OF STOCK RIGHTS

       This Assignment of Stock Rights ( this "Assignment") is entered into as
of the 6th day of June 2001, by and between HM4 ICG Qualified Fund, LLC, a
Delaware limited liability company, HM4 ICG Private Fund, LLC, a Delaware
limited liability company, HM PG-IV ICG, LLC, a Delaware limited liability
company, HM 4-SBS ICG Coinvestors, LLC, a Delaware limited liability company, HM
4-EQ ICG Coinvestors, LLC, a Delaware limited liability company, HM4 Teligent
Qualified Fund, LLC, a Delaware limited liability company, HM4 Teligent Private
Fund, LLC, a Delaware limited liability company, HM PG-IV Teligent, LLC, a
Delaware limited liability company, HM 4-SBS Teligent Coinvestors, LLC, a
Delaware limited liability company, and HM 4-EQ Teligent Coinvestors, LLC, a
Delaware limited liability company (each an "Assignor" and collectively the
"Assignors").

                                    RECITALS


       A. Each Assignor has transferred to the Assignee all of its Teligent
Shares, ICG Shares and ICG Warrants.

       B. Each Assignor and the Assignee are parties, among others, to that
certain Stock Exchange Agreement, dated May 2, 2001 (the "Exchange Agreement").

       C. Each Assignor desires to transfer to the Assignee all of the Stock
Rights, if any, associated with the Teligent Shares, the ICG Shares and the ICG
Warrants not previously transferred to the Assignee (the "ICG and Teligent Stock
Rights"). Capitalized terms not otherwise defined herein shall have the meaning
ascribed to such terms in the Exchange Agreement.

                                   AGREEMENTS

       NOW, THEREFORE, in consideration of the covenants of the Assignee
hereunder and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto, intending to
be legally bound, hereby agree as follows:

       1. ASSIGNMENT. Each Assignor hereby transfers to the Assignee and its
respective successors and assigns any and all of the ICG and Teligent Stock
Rights to the fullest extent such rights may be transferred without violation of
Applicable Law or the documents under which such rights were granted.

       2. POWER OF ATTORNEY. Each Assignor hereby constitutes and appoints the
Assignee as such Assignor's true and lawful attorney, with full power of
substitution, for it and in its name, place, and stead, but on behalf of and for
the benefit of such Assignee, (a) to demand and receive from time to time any
and all ICG and Teligent Stock Rights and to get receipts and releases



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for and in respect of the same or any part thereof and (b) to do generally all
and any such acts and things in relation thereto as such Assignee shall deem
advisable.

       3. FURTHER ASSURANCES. Each Assignor, for itself and its successors and
assigns, hereby covenants and agrees with the Assignee that such Assignor will
do, execute, acknowledge, and deliver, or will cause to be done, executed,
acknowledged, and delivered, all such further acts, conveyances, transfers,
assignments, powers of attorney, and assurances as may be required to assure,
convey, transfer, confirm, and vest unto the Assignee any and all of the ICG and
Teligent Stock Rights and to aid and assist the Assignee in collecting and
reducing the same to possession.

       4. GOVERNING LAW. This Assignment shall be governed by and construed in
accordance with the laws of the State of Delaware.


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       IN WITNESS WHEREOF, the undersigned have caused this Agreement to be
signed, all as of the date first written above.

                                   ASSIGNORS:

                                   HM4 ICG QUALIFIED FUND, LLC
                                   HM4 ICG PRIVATE FUND, LLC
                                   HM PG-IV ICG, LLC
                                   HM 4-SBS ICG COINVESTORS, LLC
                                   HM 4-EQ ICG COINVESTORS, LLC
                                   HM4 TELIGENT QUALIFIED FUND, LLC
                                   HM4 TELIGENT PRIVATE FUND, LLC
                                   HM PG-IV TELIGENT, LLC
                                   HM 4-SBS TELIGENT COINVESTORS, LLC
                                   HM 4-EQ TELIGENT COINVESTORS, LLC



                                   By:    /s/ David W. Knickel
                                      ----------------------------------------
                                   Name:  David W. Knickel
                                        --------------------------------------
                                   Title: Vice President
                                         -------------------------------------