The Tokyo Stock Exchange on Friday rejected a demand from Mizuho Securities Co. to pay 40.4 billion yen in compensation for failing to cancel a massive erroneous order placed by the brokerage, the TSE said.

The rejection makes it likely the case will go to court. Mizuho Securities has set Sept. 15 as the deadline for the TSE to make payment and said it will take legal action, including a civil lawsuit, should the TSE fail to pay up.

In a letter sent to Mizuho Securities on Friday, the TSE turned down the compensation demand, which was made on Aug. 17, the bourse said.