Seoul: The recent rally in the benchmark Korea Composite Stock Price Index (KOSPI) was largely dominated by large-cap stocks, as data revealed an uneven market performance. The rally, highlighted by significant gains in a select group of large-cap stocks, has raised questions about the broader market dynamics.

According to Yonhap News Agency, the KOSPI Large Cap Index experienced a significant surge of 18.27 percent since December 30, 2025, marking the last trading day of that year up to Monday. This data was provided by the Korea Exchange (KRX), which operates South Korea's primary stock market. In comparison, the broader KOSPI index increased by 16.4 percent, moving from 4,214.17 to 4,904.66 during the same period.

In contrast, mid-cap and small-cap stocks showed weaker performance, failing to keep pace with the broader market index. The KOSPI Mid Cap Index rose by only 5.91 percent, and the KOSPI Small Cap Index saw an increase of just 0.87 percent over the same timeframe. The mid-cap index includes companies ranked from 101st to 300th by market capitalization, while the small-cap index comprises those ranked below the 300th position.

As of Tuesday, the KRX reported that there are 813 companies listed on the main KOSPI market. Analysts, such as Shin Hyun-yong from Yuanta Securities, have noted that the bullish trend in the local stock market is primarily concentrated on large-cap shares. This concentration has led to an expansion in the relative strength of large-cap stocks compared to their smaller and mid-cap counterparts within the KOSPI.