TOKYO (AP) _ Yasuda Mutual Life Insurance Co., one of Japan's top insurers, and PaineWebber Inc., a large U.S. securities company, are forming a joint investment-trust business, newspapers reported Friday.

The two companies will set up the venture by February and start selling funds in Japan from April through Yasuda Mutual's nationwide sales network, the Nihon Keizai business daily reported.

Yasuda Mutual, which owns 8.1 percent of PaineWebber, has sent more than 100 trainees in its asset-management and system divisions for training at the New York-based company, the Nihon Keizai said.

Yasuda's affiliate, Yasuda Capital Management Co., will hold a 55 percent stake in the venture, with the remaining 45 percent to be held by PaineWebber, said the reports in the Nihon Keizai and the Yomiuri, Japan's largest newspaper.

The two companies were scheduled to announce the agreement later Friday, the reports said.

Officials at PaineWebber could not be immediately reached for comment. Phones were not answered on Christmas Eve night at the firm's New York offices.

The joint venture will be the latest effort by Japanese and U.S. financial institutions to work together here and will mark the first such investment-trust joint venture company, the report said.

In October, Wall Street investment bank J.P. Morgan and Co. and Dai-Ichi Kangyo Bank Ltd., one of Japan's largest lenders, agreed to set up an Tokyo-based mutual fund company.

Japan is currently implementing its ``Big Bang'' deregulation aimed at creating a more liberalized financial market by the early 21st century.