Group 1 - The Korean stock market reached a new high on the first trading day after the Spring Festival, boosted by the overnight rise in US stocks [1][10] - On February 19, the Japanese stock market continued its upward trend, with the Nikkei 225 index rising by 0.8% in the first half of the day [1][10] - The Korean Composite Index opened with a significant increase of nearly 3%, marking a new high, with several Korean brokerage stocks experiencing substantial gains, including SK Securities which rose by nearly 30% [3][12] Group 2 - During trading, the Korea Securities Exchange implemented a circuit breaker to halt program trading on the KOSDAQ market due to the rise in KOSDAQ 150 futures and index prices, pausing program trading quotes for 5 minutes [6][14] - In the international precious metals market, after a significant rise the previous night, gold and silver maintained a fluctuating trend, with spot gold and silver turning to an upward trend by the time of reporting [7][14]

Core Viewpoint - The Korea Exchange has activated the Sidecar mechanism to suspend algorithmic trading on the KOSDAQ market due to rapid price increases in KOSDAQ 150 futures and index, aiming to mitigate excessive market volatility and prevent systemic risks [1][2]. Group 1: Mechanism Details - The Sidecar mechanism is a routine risk control system in the Korean capital market designed to temporarily freeze algorithmic trading quotes during significant fluctuations in futures and spot indices [1]. - When triggered, all algorithmically submitted buy and sell orders are paused for 5 minutes, after which normal trading resumes automatically [1]. Group 2: Market Context - The KOSDAQ market serves as a trading platform for small and medium-sized innovative enterprises in South Korea, similar to the NASDAQ in the United States, and includes many technology, biopharmaceutical, and information technology companies [1]. - The KOSDAQ 150 index is a benchmark index composed of 150 representative stocks from this market, widely regarded as a core indicator of the overall performance of South Korean small-cap growth stocks [1]. Group 3: Global Trading Trends - Algorithmic trading is increasingly dominating trading volumes in major global capital markets, with its high-frequency and automated nature enhancing market liquidity but also potentially amplifying price volatility [2]. - Various markets, including South Korea, have implemented circuit breakers or suspension mechanisms for algorithmic trading to address the risks of amplified price fluctuations in specific market conditions [2].