South Korea's benchmark KOSPI index surged nearly 31% this month, marking its largest monthly gain since January 1998. The rally was driven by strong advances in technology shares, which helped the market overcome concerns over escalating geopolitical tensions in the Middle East.

The index’s rise was largely fueled by optimism around the artificial intelligence boom, with chip giants SK Hynix and Samsung Electronics leading the gains. In April, their shares climbed 60% and 35%, respectively.

Last week, HSBC upgraded its rating on South Korean equities from "underweight" to "neutral," noting that recent foreign capital outflows have helped ease overly crowded positions and reduce downside risks stemming from geopolitical volatility.

Beyond chipmakers, HSBC also pointed to broader growth themes in areas such as energy storage, shipbuilding, defense, and nuclear power as supporting the market's upward momentum.

This milestone performance came as Asia-Pacific markets, including the KOSPI, declined on Thursday. The index hit an intraday record high of 6,750.27 but closed 1.38% lower at 6,598.87.

Trading volume reached 676.2 million shares, with a turnover of 34.7 trillion won (approximately $234 billion). Decliners significantly outnumbered advancers by a ratio of 666 to 193.

Foreign investors net sold Korean stocks worth 1.45 trillion won, while retail and institutional investors net purchased 1.19 trillion won and 283.8 billion won, respectively.

Most large-cap stocks fell. Chipmaker Samsung Electronics opened higher after reporting strong earnings but ended down 2.43% at 220,500 won. Rival SK Hynix dropped 0.54% to 1.29 million won.

Hyundai Motor fell 4.5% to 531,000 won, while its affiliate Kia declined 3.25% to 151,800 won.

Leading battery maker LG Energy Solution dropped 2.64% to 460,500 won, and competitor Samsung SDI fell 2.39% to 695,000 won.

In contrast, electrical equipment stocks gained. Samsung Electro-Mechanics rose 0.6% to 832,000 won, and LS Electric climbed 1.83% to 278,000 won.

Shares of Doosan Robotics surged 7.83% after the company announced it is actively pursuing technical collaboration with AI chip leader Nvidia. K-pop giant Hybe jumped 4.16% to 263,000 won following strong first-quarter results.