Börsenhaftung für unterlassene Einstellung des Handels bei Störung des EDV-Handelssystems im Fall eines Mistrade – Mizuho vs. TSE

Abstract

The contribution summarizes the decision of the Tōkyō High Court of 24 July in the form of a critical analysis. The decision clarifies for the first time the relationship in Japan between the Tōkyō Stock Exchange (TSE) and securities firms participating in the trading at the exchange. The High Court deduced from the contract between the TSE and the participants not only the obligation to allow them to participate in the trading at the exchange but also to supply them with functional trading software that actually enables them to participate. Furthermore, the High Court extended a contractual limitation of liability to tort liability as long as the TSE did not act in bad faith or with gross negligence.

That facts of the case were that an employee of MIZUHO Securities entered an erroneous order into the system, which could not be reversed after the error became clear. The cause was a defect in the trading software provided by TSE. This resulted in a total loss of some 41.5 billion Yen for MIZUHO. The High Court rejected any contractual liability of the exchange but assumed a tort liability because TSE belatedly made use of its general powers to stop trading case of unusual trading. It rewarded 10.7 billion Yen damages to MIZUHO recognizing a 30 percent partial blame on the side of the securities firm.

(The Editors)