WASHINGTON, D.C. -- Cogent Communications Group, Inc. and Allied Riser Communications Corporation (Nasdaq: ARCC) today jointly announced that the companies have entered into a definitive agreement for the acquisition of ARC by Cogent. In the transaction, ARC will become a wholly owned subsidiary of Cogent and its in-building networks will be added to Cogent's national backbone and facilities. Holders of ARC common stock will receive shares of Cogent common stock in the merger. ARC's convertible subordinated notes will become convertible into Cogent common stock following completion of the merger. Cogent, headquartered in Washington, DC, is a privately held high speed Internet service provider providing end-to-end Optical Ethernet connectivity to the Internet for businesses. ARC, headquartered in Dallas, is a provider of data communications services in commercial office buildings across the U.S. and in Canada. Dave Schaeffer, chief executive officer of Cogent, said, "The acquisition of ARC will allow Cogent to integrate the nation's largest 80 Gigabit per second IP Internet backbone with the premier in-building network serving over 310 million square feet of large multi-tenant office buildings. Cogent will be uniquely capable of providing cost-effective Ethernet Internet access to small and medium size businesses in major metropolitan markets." Jerry Dinsmore, president and chief executive officer of ARC, said, "ARC believes that the combined companies are financially stronger than each company alone and the combination of ARC with Cogent will provide synergies for both companies and is a logical extension of ARC's wholesale strategy." The transaction is subject to the approval of the stockholders of both companies, the registration of the Cogent shares to be issued in the merger with the SEC, the approval for trading of the Cogent shares on the Nasdaq or a national securities exchange, and other conditions. Cogent Communications Inc. Allied Riser Communications Corp.