SK Hynix experienced a flash crash on the NXT alternative trading system's premarket at 8 AM opening, plunging 29.96% to 1,272,000 won from the previous close of 1,816,000 won due to a single-share order error. The anomaly resulted from the combination of continuous trading structure during low-liquidity periods and an investor's order mistake. This marks another instance of price distortion affecting large-cap stocks on South Korea's ATS platforms, where thin order books at market open leave prices vulnerable to execution errors.
SK Hynix Drops 29.96% on Single-Share Order Error
On the morning opening, SK Hynix traded at 1,272,000 won with a volume of only 1 share, triggering a lower-limit execution at the premarket launch. The stock price recovered to the 1.7 million won range (down 3% to 6%) within approximately 2 minutes as subsequent buy orders entered the system. However, the lower-limit execution record remained visible in the early trading window throughout the session.
Continuous Trading Structure Enables Price Distortion
The abnormal execution stems from structural differences between NXT's premarket and the Korea Exchange's pre-opening session. While KRX employs a call auction system that aggregates orders to calculate a single price, NXT's premarket operates on a continuous trading basis with immediate order execution. During periods of extremely thin trading volume at market open, empty order books combined with investor order mistakes—whether in quantity or price input—allow even 1-share trades to send prices directly to upper or lower limits.
Samsung Electronics and Kia Previously Hit by Similar Incidents
This is not the first occurrence of large-cap price distortion on NXT's premarket. Samsung Electronics, Kia, and Hanwha Aerospace have previously experienced sudden drops exceeding -20% or hitting lower limits immediately after premarket opening due to small-volume order errors. Financial authorities have expressed concern about secondary damage from price illusions, as retail investors might misinterpret fundamentally unrelated lower-limit executions as major negative news and engage in panic selling before the regular session opens.
NXT Introduces Static VI Starting September
Nextrade plans to implement countermeasures starting in September. The core measures include introducing a static volatility interruption (VI) mechanism that triggers when stock prices fluctuate sharply from the previous day's close, and switching to call auction trading for 2 minutes when VI activates to aggregate orders before execution.
FAQ
What caused SK Hynix stocks to drop 29.96% on NXT premarket?
A single-share order error at 8 AM opening combined with NXT's continuous trading structure caused SK Hynix to execute at 1,272,000 won, 29.96% below the previous close of 1,816,000 won. The price recovered to the 1.7 million won range within approximately 2 minutes.
How will NXT prevent future flash crashes on its premarket platform?
Starting in September, NXT will introduce a static volatility interruption mechanism that triggers during sharp price movements from the previous close, switching to a 2-minute call auction period to aggregate orders before execution instead of immediate continuous trading.
