The securities regulator said it had recommended a fine of JPY50,000 against the asset manager for using non-public information on the Inpex offering to make a profit for its fund.
The $6.2bn Inpex deal is one of the recent share offerings under investigation in Japan due to heavy short-selling and volumes before and after their announcements.
The SESC alleged that a fund manager at Chuo Mitsui Asset received information of the upcoming Inpex offering from a securities firm, and then sold off its existing holdings and took out short positions in anticipation the stock price would fall.
The trades generated a profit of more than JPY10m ($120,000), said SESC .
Identities of the securities company remain undisclosed.
Chuo Mitsui Asset Trust and Banking president Ken Sumida said the firm will take this regulatory violation seriously.
