Chicago-based CME Group fined the board $15,000 and ordered it to give up nearly $18,000 in profits for exceeding position limits by more than 2 percent on two consecutive dates in March 2013, according to a disciplinary notice.

Andrew Kondraski, senior manager of investment communications for the Ontario Teachers' Pension Plan, said he had no details about the circumstances of the violations.

"We've reviewed our processes to preclude any future occurrences," he added.

The pension plan had assets worth nearly $141 billion as of December 31.

(Reporting by Tom Polansek; , editing by G Crosse and Peter Galloway)