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<CONFORMED-NAME>ALLIED RISER COMMUNICATIONS CORP
<CIK>0001091535
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<STREET1>1700 PACIFIC AVE
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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT
                       PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934


                        JANUARY 9, 2002 (JANUARY 4, 2002)
                DATE OF REPORT (DATE OF EARLIEST EVENT REPORTED)

                            ------------------------

                     ALLIED RISER COMMUNICATIONS CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)


                             -----------------------


           DELAWARE                 1-15425                     75-2789492
  (STATE OF INCORPORATION)  (COMMISSION FILE NUMBER)          (IRS EMPLOYER
                                                          IDENTIFICATION NUMBER)

                             -----------------------


       1700 PACIFIC AVENUE, SUITE 400, DALLAS, TEXAS 75201-4679
               (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES,
                               INCLUDING ZIP CODE)



                                 (214) 210-3000
              (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)






<Page>



ITEM 5. OTHER EVENTS.

     On January 9, 2002, Allied Riser Communications Corporation issued the
press release attached hereto as Exhibit 99.1. The press release is incorporated
herein by reference.


ITEM 7. FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

     (c) Exhibits:
         --------

                     Exhibit
                      Number           Description
                     -------           -----------

                     99.1              Press Release, dated January 9, 2002
                                       (filed herewith)



<Page>


                                   SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, hereunto duly authorized.

                             ALLIED RISER COMMUNICATIONS CORPORATION



                                 By:   /S/ MICHAEL R. CARPER
                                       ----------------------------------
                                       Michael R. Carper
                                       Senior Vice President and General Counsel

Date:    January 9, 2002




<Page>


                                INDEX TO EXHIBITS

                     Exhibit
                      Number           Description
                     -------           -----------

                     99.1              Press Release, dated January 9, 2002
                                       (filed herewith)





</TEXT>
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<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>3
<FILENAME>a2067578zex-99_1.txt
<DESCRIPTION>EX-99.1
<TEXT>
<Page>
                                                              Exhibit 99.1
FOR IMMEDIATE RELEASE

                      ALLIED RISER COMMUNICATIONS ANNOUNCES
       ESTABLISHMENT OF RECORD DATE AND DATE OF SPECIAL MEETING TO APPROVE
                       MERGER WITH COGENT COMMUNICATIONS

DALLAS, TX (JANUARY 9, 2002) - Allied Riser Communications Corporation (NASDAQ:
ARCC) today announced that it established January 4, 2002 as the record date for
purposes of determining those stockholders entitled to vote at a special meeting
of its stockholders set for January 31, 2002 at 9 a.m. local time at its offices
in Dallas, Texas for the purpose of voting on the adoption of the merger
agreement with Cogent Communications Group, Inc. and approval of the merger.
Proxy statements with respect to the special meeting and the merger were mailed
commencing today to ARC stockholders.

"We look forward to receiving stockholder support for the Cogent merger and
encourage every stockholder to vote for this important transaction," stated
Jerry Dinsmore, chief executive officer of ARC.

As previously announced, ARC has entered into a merger agreement with Cogent
Communications Group, Inc. In the merger, holders of ARC common stock will
receive shares of Cogent common stock.

IMPORTANT INFORMATION FOR INVESTORS AND SECURITY HOLDERS

Investors and security holders are urged to carefully read the Registration
Statement and the Proxy Statement/Prospectus filed with the SEC by Cogent
Communications Group, Inc. on October 16, 2001 and the amendments thereto and
the definitive Proxy Statement filed by ARC with the SEC on January 9, 2002,
because these documents contain important information about ARC and the proposed
merger with Cogent. Investors and security holders may obtain the documents
filed with the SEC free of charge at the website maintained by the SEC at
www.sec.gov. In addition, you may obtain documents filed with the SEC by ARC
free of charge by requesting them in writing from ARC, 1700 Pacific Avenue,
Suite 400, Dallas, Texas 75201, Attention: Investor Relations, or by telephone
at (214) 210-3000.

In addition to the Proxy Statement, ARC files annual, quarterly and special
reports, proxy statements and other information with the SEC. These filings are
also available at www.sec.gov.

ARC and its directors, executive officers and certain members of management and
employees, may be deemed participants in the solicitation of proxies from the
stockholders of ARC in connection with the merger. Information about the
directors and executive officers of ARC and their ownership of ARC's stock is
set forth in ARC's Annual Report on Form 10-K for the fiscal year ended December
31, 2000. Stockholders and investors may obtain additional information regarding
the interests of such participants in the merger by reading the Proxy Statement.

SAFE HARBOR STATEMENT UNDER THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995
--------------------------------------------------------------------------------

Certain information contained in this release are not historical facts, but are
"forward looking statements" as defined in the Private Securities Litigation
Reform Act of 1995, including statements



<Page>

regarding the holding of the special meeting and the merger. Certain information
in this release concerning ARC's business may also be forward-looking, including
the future business prospects for ARC. Forward-looking information is based on
management's estimates, assumptions and projections, and is subject to
significant uncertainties, many of which are beyond ARC's control. Actual
results may differ materially from those anticipated in any forward-looking
statement as a result of certain risks and uncertainties. For further discussion
of important risk factors that may materially affect management's estimates,
ARC's results and the forward-looking statements herein, please see the risk
factors contained in ARC's SEC filings, including the Proxy Statement.


CONTACT:
Quen Bredeweg; Chief Financial Officer; ARC; 214/210-3000

</TEXT>
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