Art Technology Group, Inc. Commences Follow-On Public Offering of Common Stock.

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Nov. 10, 1999--

Art Technology Group, Inc. (Nasdaq:ARTG) announced today that it had commenced a follow-on public offering of 4,500,000 shares of its common stock at a price of $67.50 per share. In the offering, 1,425,000 shares were offered by ATG and 3,075,000 shares were offered by certain stockholders. The underwriters have been granted an option to purchase 675,000 additional shares to cover over-allotments, if any, of which ATG would sell up to 87,920 shares and the selling stockholders would sell up to 587,080 shares.

The offering is being lead-managed by Hambrecht & Quist LLC, U.S. Bancorp Piper Jaffray Inc., Thomas Weisel Partners LLC and Dain Rauscher Wessels, a division of Dain Rauscher Incorporated. Copies of the prospectus may be obtained from Hambrecht & Quist LLC, 50 Rowes Wharf, Boston, Massachusetts 02110.

ATG offers an integrated suite of Internet customer relationship management and electronic commerce products and services. ATG's solution enables businesses to understand, manage and build their online customer relationships and to more effectively market, sell and support their products and services over the Internet. ATG's Dynamo(R) product suite is designed to provide businesses with the core platform and software tools required to develop and deploy personalized, scalable and reliable e-commerce Web sites.

This release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of the shares in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.