SK Hynix has overtaken Samsung Electronics to become South Korea's most valuable company, with its market capitalization reaching $1.362 trillion. The memory-chip maker closed Monday trading 5.6% higher, pushing its valuation to 2.080 quadrillion won. Samsung ended the session down 0.1% with a market value of 2.067 quadrillion won, marking a significant shift in the Korean tech hierarchy.

The surge reflects the artificial-intelligence-driven chip boom that has energized South Korea's semiconductor sector. SK Hynix shares have more-than quadrupled this year, becoming the second Korean company to cross the $1 trillion threshold after Samsung. This AI chip demand has been a major catalyst for the Kospi, which rose 0.7% to close at a record high with year-to-date gains of 117%.

South Korea's benchmark index is outpacing regional rivals, with Japan's Nikkei up 44% and Taiwan's Taiex gaining 65% this year. The global AI infrastructure build-out continues driving investor appetite for chip stocks, particularly those positioned to benefit from next-generation computing demands.

While SK Hynix now holds the Korean crown, both companies trail Taiwan Semiconductor Manufacturing Co., Asia's first trillion-dollar company. The memory-chip specialist's ascent signals how AI demand is reshaping traditional market leadership dynamics in the semiconductor industry.