Nathalie Oriol

Time to Slow Down for High-Frequency Trading? Lessons from Artificial Markets

Summary In this paper, we focus on the French cancel order tax implemented on 1 August 2012. We question the effectiveness of the modified tax with no exemptions and we analyze its impact on market quality, measured by liquidity, volatility and efficiency. Additionally, this paper raises the question whether this tax leads to a reduction of high-frequency trading (HFT) activities and a decline in trading volume. Based on our findings we report that introduction of cancel order tax only slightly reduces HFT activities, but it significantly affects market liquidity, increases market volatility and leads to deteriorating market efficiency. We conclude that it is difficult to dissuade investors from entering into unproductive trades and eliminate negative outputs of HFT (such as price manipulations) through tax, without altering the benefits of HFT like liquidity provision and efficient price discovery.

Heterogeneous investors and trading platforms competition

Purpose - – The purpose of this paper is to consider competition’s issues between European market firms, such as Euronext, and multilateral trading facilities, following Markets in Financial Instruments Directive’s enforcement. This new domestic competition is adding to the existing international competition among financial centers. While diversification of local trading services can improve the international competitiveness of a financial center, the fragmentation of order flows can harm its attractiveness. Design/methodology/approach - – The theoretical setting analyzes the interaction between heterogeneous who experiment network externalities, and heterogeneous local trading services providers (alternative platforms and incumbent) in an international context. The authors compare two forms of organizations of the market: a consolidated market, and a fragmented market with alternative platforms – in both cases, in competition with a foreign universe. Findings - – The results of this study point out the importance of the trade-off between diversification and externalities. With alternative platforms entry, enhanced competition decreases fees and redistributes informed investors between the foreign market and the domestic one. The increase of domestic platforms’ number then has more complex effects on externalities (of information and liquidity). When the liquidity externalities are low, the diversification of financial platforms increases the number of investors on domestic centers. When liquidity externalities are not negligible, despite the decrease of fees, this same diversification orientates more informed investors to the foreign center. Originality/value - – This model is the first to analyze jointly the internal and international competition of trading platforms with heterogeneous investors.