Senior officials at Cresvale International Ltd., which is at the center of a massive fraud investigation, offered rebates amounting to 500 million yen to a former vice president of drink maker Yakult Honsha Co. for the purchase of privately placed bonds it sold, it was learned Thursday.

The bonds, which were issued by Princeton Economics International Ltd. of the United States via a paper company, were sold in huge quantities to Japanese companies by Cresvale, a brokerage subsidiary of PEI. The bonds are now considered irredeemable.

According to the sources, Akira Setogawa, head of Cresvale's Tokyo branch, acknowledged the rebates had been extended to Yakult during recent questioning by the Securities and Exchange Surveillance Commission, the sources said.