Major Japanese banks will give Citigroup Inc. a 1.7 trillion yen line of credit, sources said Friday, as the U.S. financial conglomerate makes a bid to acquire Nikko Cordial Corp.

The syndicated loan by the banks, including Mizuho Corporate Bank, Bank of Tokyo-Mitsubishi UFJ and Sumitomo Mitsui Banking Corp., will be the biggest ever offered here, topping the 1.28 trillion yen for Internet firm Softbank Corp.'s acquisition of Vodafone Group PLC's Japanese operations last year.

The cash-flush U.S. group appears to be trying to sidestep any criticism it might face as a foreign bank buying a Japanese brokerage by strengthening its relationships with Japanese banks through taking a syndicated loan from them, the sources said. Citigroup launched a friendly tender offer for Nikko Cordial on March 15 in the hope of making the scandal-tainted No. 3 Japanese brokerage a wholly owned subsidiary. The offer will last until April 26.