Exchange to Operate Special Aftermarket Monitoring TF Through Year-End..."Preventing Volatility and Unfair Trading"

Dedicated Teams for Monitoring, Prevention, and Short Selling Oversight

1.1 Trillion Won in Trading Value and 86% Execution Rate

Volatility Mitigated Through VI Triggers

The Korea Exchange (KRX) has decided to operate a special Aftermarket Monitoring Task Force (TF) through the end of the year.

Korea Exchange

According to the Exchange on September 21, the task force is composed of a total of nine members—three each responsible for monitoring, prevention, and short selling oversight—who will be dedicated exclusively to monitoring the aftermarket and strictly responding to unfair trading activities. The Exchange plans to extend the operating hours for unfair trading prevention measures and to build a nighttime monitoring infrastructure, such as by integrating analyses of transaction data from both the regular trading session and the aftermarket.

During the first week after the establishment of the aftermarket (September 14–18), the average daily trading volume came to 54.85 million shares, while the trading value totaled 1.1 trillion won. During this period, individuals accounted for 90.4% of the trading value, foreign investors for 6.7%, and institutions for 2.6%, which is 4.6% of the total trading value recorded during the regular trading session.

Out of 2,763 listed securities, 2,379 (86.1%) were actually executed in trades, meaning that investors now have substantially broader choices compared to the previous situation, where around 600 stocks were available. Issues with extremely low liquidity or those requiring market oversight have been excluded from aftermarket trading eligibility.

To ensure strict market management, the Exchange has introduced the same volatility interruption (VI) mechanism in the aftermarket as used in the regular session, and operates a market maker system. It is rare for major overseas markets such as the United States and Japan to adopt volatility interruption mechanisms or market maker systems in their after-hours markets.

The number of VI triggers stood at 1,112 on the first day, but then declined steadily to 553 as of September 18. This slightly exceeds KRX's daily average VI activation in the regular session this year, which is 494. For high-low volatility—a metric showing market volatility by measuring the gap between the intraday highest and lowest prices—the aftermarket recorded five consecutive days of levels lower than those of the regular trading session.

The Exchange stated, "The number of VI triggers does not necessarily represent market volatility. Rather, it means that, by activating the VI, transactions at abnormal prices are prevented and the market can discover an equilibrium price through single-price auctions, thereby mitigating fluctuations."

This content was produced with the assistance of AI translation services.