TOKYO (AFP) - Japan's Mizuho Financial Group has declined an award it was set to receive for transparency after getting told off by regulators for lending money to gangsters.

Mizuho Bank, Japan's third-biggest, has been under fire since it came to light that it had processed hundreds of transactions worth about 200 million yen (S$2.57 million) for "anti-social forces", a common term for Japan's yakuza mobsters.

A group of securities analysts had selected Mizuho Financial Group as the best banking firm for information transparency, saying "the company was praised for its attitude for proactively disclosing information that may not necessarily benefit the firm or even about the company's weak points".

But Mizuho FG declined the honour, the Securities Analysts Association of Japan said on Monday as it released the annual report.

It would have been Mizuho's third honour for transparency.

The Financial Services Agency admonished the bank last week for taking "no substantial steps" in dealing with the issue after it was first discovered two years ago, and pointed to "serious problems" with its compliance monitoring.