Asia’s AI Rally Hides 42% Concentration Risk in Korea, Taiwan

South Korea’s Kospi index has surged more than 80% this year, hitting one fresh high after another. Taiwan’s Taiex has repeatedly posted new records. The rallies share a common engine: a narrow group of semiconductor giants riding the artificial intelligence boom. The concentration has reached levels that make the headline index gains a poor proxy for broad market health. Samsung Electronics and SK Hynix together accounted for a record 42.2% of the Kospi in May, according to Manulife Investment Management. Taiwan Semiconductor Manufacturing Company (TSMC), with a market capitalization of about NT$58 trillion ($1.85 trillion), now represents more than 40% of the Taiex, UOB data show. For an investor buying the Kospi or Taiex as a broad Asia exposure, the bet is overwhelmingly a wager on a handful of AI hardware names.

The 42% Kospi and 40% Taiex Concentration

Goldman Sachs strategist Tim Moe described the driver in blunt terms. “In a word, it’s the AI hardware theme that’s clearly what is propelling things,” he told CNBC. Taiwan derives well over 80% of its equity revenue exposure from AI-related streams, Moe estimated, while South Korea stands around 60%. The earnings power behind those numbers is extraordinary. Goldman expects South Korean earnings growth could surge 300% this year. Samsung Electronics’ market capitalization pushed past $1 trillion last week as investors chased AI-linked stocks.

The index-level optics mask how little of the domestic economy is actually participating. JPMorgan’s head of Korea and Taiwan equity strategy, Mixo Das, noted that both markets have always been more a reflection of global demand than domestic demand, given the dominance of exporters. “This remains the case; it is simply that global demand has become very concentrated in AI at present,” Das said. The concentration is not a new feature of these markets; the AI cycle has, however, amplified it to an extreme. A trader who bought the Kospi at the start of the year has effectively bought a basket where two memory-chip makers dictate the return.

Supply Chain Chokepoints and Energy Import Risk

The transmission risk runs through the physical supply chain. Taiwan and South Korea sit at the center of a manufacturing ecosystem that depends on specialized chemicals, photoresists, and high-purity gases. A disruption to any of these inputs could halt production lines. Moe laid out the scenario directly: “If you just can’t get them, and therefore you have to stop your production, it would not take a genius to think that the stocks would correct.” The geopolitical flashpoints that could interrupt those flows are not hypothetical. Tensions in the South China Sea or a blockade affecting key shipping routes would hit the semiconductor supply chain within days.

Energy imports add a second layer of vulnerability. Both economies are large net importers of oil and gas. Jamie Mills O’Brien, investment director at Aberdeen Investments, said the two markets “sit on the wrong side of the terms of trade as large energy price importers,” particularly with oil prices rising sharply on Middle East tensions. Higher energy costs would squeeze purchasing power and erode the competitiveness of the very exporters driving the equity rally, even if AI demand stays strong. The same AI boom that lifts chip exports also leaves the broader economy more exposed to an oil shock that raises input costs across manufacturing and transportation.

Taiwan’s Regulatory Nod to TSMC and the $30B–$40B Inflow

Taiwan’s regulators recently relaxed limits on how much domestic funds can allocate to a single stock, a move widely interpreted as a green light for more TSMC exposure. UOB chief investment officer Qi Wang estimated the change could channel $30 billion to $40 billion into the chipmaker alone. “Some people say Taiwan is just a one-trick pony. That’s just TSMC,” Wang said. “Longer term, it does increase the concentration risk for both the economy and the stock market.”

The regulatory shift risks reinforcing the very dynamic that makes the Taiex increasingly detached from Taiwan’s domestic economy. Moe contrasted the two markets: South Korea’s equity universe still captures shipbuilding, defense, power equipment, and even the “K-culture” trade, making its rally more reflective of broader industrial strength. Korea’s equity gains are better aligned with strong exports and swelling current-account surpluses, he added. Taiwan’s market, by contrast, has become overwhelmingly tied to global semiconductor demand and to TSMC’s order book. A slowdown in data-center capital spending would hit the Taiex disproportionately, while the Kospi could find some offset in its non-tech sectors.

The Double Risk for Global Allocators

Florian Weidinger, chief executive officer of Santa Lucia Asset Management, warned that many global investors seeking diversification may unknowingly be doubling down on the same AI trade. Buying U.S. megacap technology stocks and Asian benchmarks dominated by semiconductor giants creates overlapping exposure. “If that were to break,” he said, “a lot of allocators will wake up with double risk.”

The crowding is not theoretical. Das noted that 40% to 45% of the S&P 500 is AI-related by some measures, with even higher levels in Taiwan and Korea. A portfolio that holds the S&P 500, the Kospi, and the Taiex is effectively making a concentrated bet on the same AI capex cycle. History offers parallels. Denmark’s market, heavily dependent on Novo Nordisk, slumped when obesity-drug demand concerns surfaced. Saudi Arabia’s equity market, dominated by Saudi Aramco, struggled when oil prices fell. Both were among the world’s weakest-performing markets at the end of last year. Concentration can be self-reinforcing in a bull market; when sentiment shifts, the unwind is compressed.

Goldman Sachs (GS), whose strategist Tim Moe flagged the risks, carries an AlphaScala Alpha Score of 56 out of 100, a moderate reading that suggests the stock itself is not immune to crowded-trade dynamics. GS stock page For the Korea and Taiwan benchmarks, the next stress test will arrive with quarterly earnings from Samsung Electronics and TSMC. Any softening in AI-related guidance could rapidly unwind the concentration premium that has driven the indexes to record highs. A sustained pullback in data-center capital spending or a geopolitical shock that disrupts the specialty-chemical supply chain would turn the concentration from a tailwind into a forced deleveraging event. Until then, the headline index prints will look strong, even if they say less about the underlying economies than the market-cap weights suggest. The FLKR’s Volcano Trade Rests on Samsung’s Earnings and a Stable Won illustrates how single-stock narratives can dominate entire country ETFs, a dynamic now playing out across the Kospi and Taiex. For broader market analysis, the concentration risk in Asia’s AI trade is a reminder that index-level returns can be misleading when a handful of names drive the entire move.