By Sakura Murakami

TOKYO (Reuters) -The Japan Securities Dealers Association (JSDA) said on Wednesday client data was leaked from brokerage Mitsubishi UFJ Morgan Stanley Securities, without specifying a time period for the leaks.

The securities company shared 499 cases of confidential information from 401 clients to some of its corporate bond issuers, according to a statement from JSDA

Mitsubishi UFJ Morgan Stanley Securities said in a statement the JSDA had reprimanded the securities firm and ordered it to improve its data protection.

“We take this incident very seriously and will work to strengthen our internal management,” Mitsubishi UFJ Morgan Stanley Securities said in its statement, released on Wednesday afternoon. The statement didn’t comment on the number of cases of leaked information.

“We hope to win back the trust of our customers and others involved by implementing our prevention measures,” the statement said. The leaked information has either been returned or destroyed in the meantime, the brokerage said.