Korea Exchange Pauses Program Buying for Five Minutes as KOSPI Jumps More Than 4%

South Korea's stock exchange temporarily suspended program buying on Wednesday morning after a rapid rise in equity-index futures triggered a market safeguard. The Korea Exchange activated a buy-side sidecar at 9:53 a.m. local time on October 28, halting the affected program trades for five minutes.

The action followed a sharp advance in the benchmark KOSPI index. After opening 2.23% higher, the index was up 255.92 points, or 4.54%, at 5,894.26 as of 9:55 a.m., according to figures reported by Yonhap and the Korea JoongAng Daily. Those figures describe a point in morning trading, not the market's closing level.

The safeguard is designed to slow automated trading when futures prices move rapidly. A buy-side sidecar is triggered when the KOSPI 200 futures index rises at least 5% and remains above that threshold for one minute. It pauses relevant program-buy orders for five minutes rather than closing the entire stock market or suspending all individual share transactions.

The rally followed a strong overnight performance by US technology shares and new earnings figures from South Korean memory-chip producer SK hynix. Before the local market opened, the company reported record third-quarter revenue and operating profit amid demand for high-bandwidth memory and other chips used in artificial-intelligence infrastructure.

SK hynix also announced a large shareholder-return program for 2026. Investors interpreted the combination of strong earnings and planned distributions as support for semiconductor shares, which carry substantial weight in the Korean equity market.

The exchange's action is notable because sidecars can be activated during sharp upward moves as well as selloffs. It does not, by itself, mean regulators expect a market crash or that any company has been accused of misconduct. Its purpose is to provide a brief interruption in automated order flow when futures markets exceed a preset movement threshold.

The trading surge occurred ahead of a scheduled US Federal Reserve interest-rate announcement, another event investors were monitoring. Whether the early advance persisted through the rest of the Korean session was not established by the morning figures used in this report.