4  market of the Tokyo Stock Exchange has reached around 40 percent (Chart 3).3 Equally, there is a view that the share of HFT in Japanese stock futures has reached a somewhat high level due to the introduction of IT systems designed for high-speed order processing. Positive assessments of HFT can be summarized as follows.
First, there is a view that HFT has improved market liquidity as HFT players engage in "passive market making" against other investors by simultaneously placing a vast amount of "buy" and "sell" orders in order to exploit arbitrage opportunities on bid-ask spreads.