Kospi tumbles 6% as AI investors fear rally may be overblown. A bigger crash coming closer?

South Korea's Kospi index declined 6% on valuation concerns surrounding the artificial intelligence rally, signaling potential weakness in semiconductor and tech-dependent equities globally. The selloff in Samsung Electronics and SK Hynix—critical supply-chain players for AI chip production—raises questions about margin sustainability and demand normalization across memory chip markets.

Foreign investor net selling activity in South Korean equities reflects broader portfolio rebalancing away from stretched valuations in AI-exposed names. This outflow pattern typically precedes spillover effects in correlated U.S. technology and semiconductor holdings, particularly companies with heavy exposure to Korean supply chains and earnings forecasts built on AI upside scenarios.

The concurrent weakness in battery and shipbuilding sectors suggests broader cyclical concerns beyond pure AI euphoria, indicating macro uncertainty about global growth momentum. Investors may be repricing risk premiums on earnings quality assumptions, especially for companies trading at elevated multiples relative to fundamentals.

Sector implication: Technology and semiconductor sectors face renewed scrutiny on earnings sustainability. Battery and industrials weakness signals demand caution, while foreign capital flows out of emerging markets suggest risk-off sentiment may accelerate in developed equity markets, particularly among AI-thematic and high-beta growth names.