Closing Call Auction Prices as Settlement Prices for Derivatives Contracts and Price Manipulation

Previous literature emphasizes the importance of a closing call auction system because it can not only improve the price discovery effect, but also mitigate the possibility of price manipulation. However, Korea Exchange, which has adopted a closing call auction system, has still suffered from the price manipulation, most cases of which are likely to be related to the derivatives contracts. Based on this environment, this paper investigates why KRX experiences the closing price manipulations so much, even though it adopted the closing call auction system. Generally, a price manipulation occurs when the legal/administrative penalty is less than the expected economic gain or when a specific market structure increases an incentive to manipulate the price. In this paper, we find that the adoption of a closing call auction price as a settlement price for KOSPI derivatives contracts strengthens the incentive for closing price manipulation, which is supported by Kyle (2007). Kyle (2007) shows that if a closing price is used as a settlement price and investors can execute the ‘market-on-expiration orders’ surely, the derivatives with cash settlement are susceptible to the price manipulation such as squeezing or cornering, equally as the derivatives with physical settlement. As such, KRX is the only financial market that satisfies the above conditions. This paper tries to verify this argument by introducing the Hong Kong Exchange case, the Korean ELS-related manipulation case and the Deutsche Bank case. Therefore, we strongly recommend changing the settlement price of KRX derivatives contracts into an average price, which is similar with the well-developed financial markets.