Nortel Networks, International Business Machines, Matsushita Electric Industrial, and five other companies unveiled an Internet market for computer and telecommunications products that could cut their supply costs as much as 15%. Computer makers and suppliers will sell and buy electronic products and services on the exchange, called e2open.com. The venture will be independently operated by managers selected by investors Crosspoint Venture Partners and Morgan Stanley Dean Witter, Nortel said. The venture is backed by $200 million from investors and founding members. The founding electronics companies will own 50% and Crosspoint and Morgan Stanley, 20% each, said Masaharu Kimura, vice president of IBM Japan, at a press conference in Tokyo.