Samsung confirms May 21 18-day strike; KOSPI plunges 6% to 7,493

Samsung union rejects government mediation May 14, forces all-out strike starting May 21 with 50,000 workers. Chipmakers tumble May 15—Samsung -8.6%, SK Hynix -7.7%—triggering KOSPI's worst single day in months. JPMorgan estimates 210–310 billion won operating profit hit; Seoul estimates 4 trillion won direct and indirect damage. HBM lines take full impact; global memory supply chain braces for spillover.