South Korea’s stock market ascends to sixth place worldwide, driven by AI chip boom

South Korea’s stock market has surged into a new league, overtaking India to become the world’s sixth-largest equity market and pushing past bourses in Britain, Germany and France. But the rally’s speed has also sharpened debate over how much of the boom rests on just two chipmakers, SK Hynix and Samsung Electronics.

According to reporting in The Guardian, both companies have recently joined the trillion-dollar valuation club, powered by extraordinary demand for memory chips used in artificial intelligence systems. SK Hynix’s shares have climbed roughly 1,000% over the past year, while Samsung has gained about 500%, helping drive the Kospi to repeated records and a peak of 8,880 this week. That marked a 220% rise over 12 months.

Goldman Sachs has lifted its 12-month target for the index to 9,000, describing the earnings surge in semiconductors as a once-in-a-generation move. The scale of the advance has transformed South Korea’s market standing, with some analysts saying the country has become the first outside the United States to host more than one company worth at least $1tn.

The gains have also helped reshape the wider Asian market landscape. Taiwan has benefited from the same AI-fuelled demand, with TSMC remaining central to Nvidia’s supply chain, while Tokyo’s Nikkei 225 has also hit record highs as investors continue to rotate into AI and chip-related shares. SoftBank Group has overtaken Toyota as Japan’s most valuable listed company, underlining how strongly capital is favouring technology and hardware.

Peter Kim, global investment strategist at KB Securities, told The Guardian that the shift felt dramatic and pointed to a change in where global market leadership is being found. He said the old assumption that the most important companies would be in the United States, while Asia merely followed behind, now looks less certain.

That confidence is not universal. Some market participants worry the Kospi has become too concentrated, leaving it vulnerable to any slowdown in AI capital spending or disruption in semiconductor supply chains. Investment director Russ Mould of AJ Bell said the share-price patterns in the sector bear uncomfortable similarities to the run-up to the technology bust in 2000, although he added that the AI era may ultimately prove different.

There are reasons investors remain enthusiastic. The biggest buyers of AI infrastructure, including Meta, Amazon, Alphabet and Microsoft, continue to pour money into data centres and computing power. SK Hynix and Samsung, together with US rival Micron, are among the key suppliers meeting demand for advanced memory chips, a part of the market that has moved from being viewed as cyclical and unexciting to central to the AI build-out.

Still, the concentration is striking. KB Securities says Samsung and SK Hynix may have accounted for as much as 70% of the Kospi’s rise in 2026, a level of dependence that leaves the benchmark unusually exposed to any change in the global AI investment cycle. Swissquote analyst Ipek Ozkardeskaya also noted that the Kospi’s volatility index jumped to an exceptionally high level this week, even as the market rallied, suggesting investors are rushing in for fear of missing out rather than because they are calm.

For now, however, the momentum remains firmly with South Korea and the wider semiconductor supply chain. Nvidia chief executive Jensen Huang has been in Taiwan making upbeat comments about the region’s role in AI manufacturing, and is expected to visit South Korea as the contest to secure chip capacity intensifies. The market’s message is clear: after years in which Asia was often treated as a secondary story, investors are increasingly treating it as the centre of the AI trade.