Japan's largest credit card service provider plans to join the seven-company financial alliance being led by Sanwa Bank, one of the nation's largest commercial banks, sources said Monday.

JCB Co., whose cards are used by at least 20 million Japanese, plans to join forces with the seven other firms in marketing a variety of financial products by combining their customer bases, sources at JCB said.

The seven members are Universal Securities Co., Toyo Trust & Banking Co., Koa Fire & Marine Insurance Co., Daido Mutual Life Insurance Co., Taiyo Mutual Life Insurance Co., and Nippon Fire & Marine Insurance Co.

Under the deal the group would work on developing new financial products that make use of the various companies' services and enhance cooperation in promoting existing products, they said.

Many in the financial industry see the lack of a credit card company as a weakness in the alliance, and are doubtful as to whether the credit card giant will engage in full participation in the Sanwa alliance.