OSAKA (Kyodo) Resona Bank was penalized after being found by the Osaka Regional Taxation Bureau not to have paid some ¥250 million in stamp taxes over three years through last September, several sources close to the case said Tuesday.

The Osaka-based core unit of Resona Holdings Inc. said it has already paid all the taxes that were due. The tax amount including the penalty is estimated at some ¥280 million, according to the sources.

About 600,000 Resona papers lacked required revenue stamps, the sources said.

Resona Bank says its staff forgot to put the stamps on money receipts that were handed to customers, a fact it was not aware of.

The bank said the nonpayment was not intentional and it has paid all the taxes as instructed by the tax bureau.