Posted: 03/2000

NEXTLINK and Concentric to Merge in $2.9 Billion
Stock Swap

NEXTLINK Communications Inc. (www.nextlink.com)
and Concentric Network Corp. (www.concentric.com)
have agreed to merge in a stock-for-stock deal worth $2.9 billion.

Officials of the companies say the merger, expected to close in the second quarter,
will create an unbeatable combination of local access (NEXTLINK) and national reach
(Concentric).

The companies say NEXTLINK customers will benefit from Concentric’s VPN, application
hosting and high-speed Internet offerings; Concentric’s customers will benefit from
NEXTLINK’s voice offerings.

The new company will be located in McLean, Va., where NEXTLINK recently moved.
Concentric’s operations will continue to be in San Jose, Calif.

Dan Akerson, NEXTLINK’s chairman and CEO, will remain chairman and CEO of the combined
company. Henry R. Nothhaft, chairman, president and CEO of Concentric, will become vice
chairman of NEXTLINK and sit on its board.