卖压主要集中在 Samsung Electronics Co. 与 SK Hynix Inc.。两家公司受 AI 记忆体需求推动，估值与获利前景强劲，却也因单一股票权重过高，迫使全球基金减码以降低集中度风险。对照 MSCI Emerging Markets Index，Hynix 的权重已相当于 Tencent Holdings Ltd. 与 Alibaba Group Holding Ltd. 之和，两家韩国晶片商再加上 Taiwan Semiconductor Manufacturing Co. 合计占比超过 25%，并贡献了该指数 2026 年迄今超过 70% 的涨幅。
这使整个新兴市场资产类别越来越像 AI 基础设施的代理标的。Roundhill Memory ETF 早在 4 月初推出，韩国两家晶片商几乎占其投资组合的一半，已吸引 87 亿美元净流入，成为史上成长最快的 ETF。作者认为，外资撤出不一定是看空 Kospi，而更可能是为维持分散配置；但在 AI 主导的行情中，宽度偏弱、赢家通吃与更高回撤风险将持续考验专业投资者。
South Korea’s stock market is up 71% this year, making it the world’s best performer, yet global investors who own about 39% of the Kospi have sold almost $60 billion since Jan. 1. Domestic retail participation has surged, with brokerage cash deposits reaching 137 trillion won ($91 billion), about two-thirds higher than six months ago, while margin loans are at record levels.
The heaviest selling is in Samsung Electronics Co. and SK Hynix Inc., whose AI-driven memory-chip strength has made them among the world’s most profitable companies. But their success is also creating concentration pressure: in the MSCI Emerging Markets Index, Hynix’s weight now equals Tencent Holdings Ltd. plus Alibaba Group Holding Ltd., and the two Korean chipmakers plus Taiwan Semiconductor Manufacturing Co. account for more than 25% of the benchmark and over 70% of its 2026 gains.
The result is an increasingly narrow AI-led rally that looks like an infrastructure proxy rather than a broad market advance. Retail investors have embraced the theme, as shown by the $8.7 billion inflow into the concentrated Roundhill Memory ETF. For professional managers, the dilemma is whether to accept concentration risk in order to keep up with benchmark returns, or stay diversified and potentially leave money on the table.