Exhibit (a)(10) - Joint Press Release issued by Thomson and the Company on June 28, 2000. The Thomson Corporation [LOGO] Toronto Dominion Bank Tower, Suite 2706 PO Box 24, Toronto-Dominion Centre Toronto, Ontario M5K 1A1 Tel (416) 360-8700 Fax (416) 360-8812 www.thomson.com News Release FOR THOMSON: FOR PRIMARK: - ----------- ----------- Investor Contact: Vicki Van Mater - ---------------- Director of Corporate John Kechejian (703) 790-7613 Communications vicki.vanmater@primark.com Vice President, Investor Relations (203) 969-8700 john.kechejian@thomson.com Media Contact: - ------------- Janey Loyd Vice President, Corporate Communications (203) 969-8700 janey.loyd@thomson.com For Immediate Release - -------------------------------------------------------------------------------- THOMSON AND PRIMARK RECEIVE U.S. DEPARTMENT OF JUSTICE REQUEST FOR ADDITIONAL INFORMATION ON THOMSON'S ACQUISITION OF PRIMARK - -------------------------------------------------------------------------------- TORONTO, ONTARIO, and WALTHAM, MA, June 28, 2000 - The Thomson Corporation (TSE:TOC) and Primark Corporation (NYSE/PCX: PMK) announced today that Thomson and Primark have received a request for additional information and documentary material from the Antitrust Division of the Department of Justice following from the DOJ's routine review of the proposed acquisition of Primark by Thomson. The waiting period under the Hart-Scott-Rodino Act will expire ten days after Thomson substantially complies with the DOJ's request. Thomson and Primark intend to comply substantially and promptly with the request. The Thomson Corporation (www.thomson.com), with 1999 revenues of US$5.8 billion, is a leading, global e-information and solutions company in the business and professional marketplace. The Corporation's common shares are listed on the Toronto and London Stock Exchanges. # # #