Seoul: More stocks listed on the benchmark Korea Composite Stock Price Index (KOSPI) have declined than advanced in recent weeks despite the market rally, the bourse operator said Sunday, suggesting that investment is increasingly concentrated in a handful of heavyweight semiconductor stocks.

According to Yonhap News Agency, the Korea Exchange (KRX) reported that an average of 210 KOSPI-listed stocks advanced, while 586 declined and the remainder were unchanged during the two-week period from May 26 through Friday. This trend unfolded even as major market heavyweights posted strong gains, highlighting a disparity in stock performance.

Shares of top-cap Samsung Electronics Co. and its chipmaking rival SK hynix Inc. rose 13.72 percent and 14.32 percent, respectively, over the cited period, indicating a significant focus on these semiconductor giants. On May 27, the KOSPI jumped 2.55 percent, yet only 72 stocks advanced, whereas 713 stocks rose on May 22, when the KOSPI posted a modest 0.41 percent gain, according to KRX data.

Interestingly, when the KOSPI closed 1.84 percent lower on Thursday, 400 stocks advanced, outnumbering 389 decliners. This pattern suggests a volatile and concentrated investment landscape, emphasizing the dominance of semiconductor stocks.

"The current market concentration cannot be explained solely by investor sentiment," said Noh Dong-gil, an analyst at Shinhan Securities. "Samsung Electronics and SK hynix have evolved beyond market leaders to become common underlying assets across a wide range of financial products." The divergence has fueled expectations that investors will continue to concentrate on a handful of top-cap chip leaders that are driving the KOSPI rally.