KOSPI rebounds 4% as Samsung, SK Hynix lead tech recovery
In brief
- KOSPI dropped 9.99% on June 23 to 8,203.84, triggering a 20-minute trading halt
- Samsung and SK Hynix each fell over 12%, then led the recovery bounce
- Two stocks control over 50% of index market cap, creating structural fragility
- SK Hynix surge driven by AI chip demand; company posted $63.1B 2025 revenue
The June 23 Crash and Recovery
The decline was steep enough to trigger a 20-minute trading halt, a circuit breaker activated after concerns about overheated tech stocks and regulatory warnings. Both Samsung and SK Hynix fell by more than 12% each, dragging the index down by 9.99%. The crash capped a period of extreme volatility that had seen the KOSPI surge 8.2% just two weeks earlier on June 9, when Samsung gained approximately 9.3% and SK Hynix ripped higher by more than 15%.
The recovery followed quickly. SK Hynix briefly surpassed Samsung in valuation during the turbulence, a symbolic moment that underscored just how dramatic the swings had become. The two stocks' outsized influence means the KOSPI's fate hinges on a narrow slice of the market.
Concentration Risk in Focus
The KOSPI has dropped 15% from its recent peaks before recovering. This volatility has spooked international investors. Foreign investors have been net sellers throughout the chaos, dumping billions in Korean stocks. Yet their concerns appear centered on market concentration risk rather than any fundamental deterioration in the underlying businesses.
South Korean authorities issued warnings about overheated tech stocks and leveraged ETFs in the lead-up to the crash. The regulatory alarm reflects a deeper structural problem: a market where two stocks control more than half the index weight is inherently fragile.
SK Hynix's AI-Driven Surge
SK Hynix's rise has been powered by insatiable demand for high-bandwidth memory chips used in AI training and inference workloads. The memory chip maker posted record revenue of 97 trillion won, roughly $63.1 billion, for 2025. Net profit hit 42.9 trillion won, approximately $27.9 billion. Those numbers reflect genuine strength in the AI infrastructure buildout, not speculation.
Still, the concentration remains the core risk. When two companies can move an entire national index by 10% in either direction within days, investors face a structural vulnerability that no single company's earnings growth can fully offset.
