The Japan Securities Dealers Association said Wednesday it has imposed a penalty of 300 million yen ($2.23 million) on SMBC Nikko Securities Inc. for market manipulation, matching the highest fine previously issued by the organization.

According to the JSDA, SMBC Nikko illegally propped up the prices of 10 individual stock issues to stabilize them last year in "block offering" transactions.

The fine imposed on the brokerage by the JSDA is equal to that issued to Nomura Securities Inc. in connection with an insider trading scandal in 2012.

Some former SMBC Nikko executives have been charged in the scandal, while its President Yuichiro Kondo announced in November last year that he would resign once he finishes leading the brokerage's revamp.

Last month, the Tokyo District Court ordered SMBC Nikko to pay a fine of 700 million yen and a forfeiture of 4.47 billion yen for violating the financial instruments and exchange law.

Teruya Sugino, former deputy head of the brokerage's equities division, was sentenced to 18 months in prison, suspended for three years.

In a block offering transaction, a brokerage mediates between large shareholders who want to sell chunks of shares and investors hoping to buy them during off-hours trading. The brokerage profits from the difference between the purchase and sale prices.

Related coverage:

SMBC Nikko president to resign over trading scandal

SMBC Nikko ordered to suspend some operations over trading scandal