Asian Stock Concentration Reaches Historic Levels as AI Rally Forces Fund Rebalancing
Three chipmakers now account for nearly a third of Asia's largest equity index, creating a concentration risk that has forced active fund managers to sell their best-performing stocks. TSMC, Samsung, and SK Hynix have become so dominant in regional benchmarks that many portfolio managers face a structural problem: they cannot hold enough of these stocks without breaching internal risk limits.
TSMC alone comprises 41.5% of Taiwan's main index. Samsung and Hynix together make up 55% of South Korea's KOSPI. This means these indexes function less as diversified market measures and more as bets on one or two companies.
The three stocks have gained 52%, 159%, and 184% respectively so far this year, riding an AI-driven rally. Yet their dominance has forced managers like Sam Konrad at Jupiter Asset Management to sell positions in TSMC, Samsung, and MediaTek despite strong fundamentals, simply to keep portfolio concentration within acceptable levels.
Forced Selling Accelerates Fund Outflows
Active managers selling large positions has added pressure to regional markets, particularly the Korean won. The dynamic has also created a feedback loop: as concentration worsens, more active funds find it harder to keep pace with benchmarks, accelerating outflows to passive funds.
Over the last five years, Asia's active funds have lost $269 billion while passive funds have gained $510 billion. A quarter of that passive inflow occurred in just the last six months, according to BNP Paribas analysis.
The scale is unprecedented. William Bratton, head of cash equity research for Asia-Pacific at BNP Paribas Securities, said the recent inflows into passive funds have "no precedent across the last 10 years."
Sector and Geographic Imbalance Widens
The rally has not broadened across sectors. Information technology stocks have surged while consumer staples and healthcare have lagged. At the country level, the picture is starker: while the MSCI Asia Pacific ex-Japan index is up 27% year-to-date, the same index excluding South Korea and Taiwan is down 4%.
This mirrors the Magnificent Seven concentration in U.S. markets, but the Asian version has unfolded faster and more severely. The concentration is also more extreme: the three Asian stocks represent a larger share of their benchmarks than the Magnificent Seven do of the S&P 500.
Stock Pickers Shift Strategy
Active managers have responded by moving down the supply chain. Isaac Thong at Aberdeen Investments recently added ASMPT and Grand Process Technology, both mid-sized chipmaking suppliers, to avoid the concentration trap of owning the three dominant stocks.
Konrad has allocated nearly half his fund to Taiwan and South Korea but focuses on electronics makers Hon Hai and Quanta, along with chip designer MediaTek, rather than the three largest positions. He said his fund's approach differs significantly from the benchmark and from peer strategies, which has helped performance.
Volatility Follows Concentration
The downside of extreme concentration appeared in recent sessions. South Korean stocks fell 12% and Taiwan dropped 6% from record highs as investors questioned AI valuations. These sharp moves reflect how vulnerable regional markets have become to sentiment shifts affecting just a handful of stocks.
Foreign portfolio rebalancing has created unusual flows. A record $27.9 billion left South Korean equities in May alone, while U.S.-domiciled funds poured $20.4 billion year-to-date into South Korea and Taiwan.
Rupal Agarwal, Asia quant strategist at Bernstein, said the concentration "we have never seen before" has become the defining feature of Asian equities.
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