Today’s market buzz

WDC sank despite a beat as cautious guidance and margin remarks weighed. Sandisk fell after a double beat as next-quarter revenue midpoint missed consensus. Korea's KOSPI plunged as SK hynix flash-crashed premarket and Samsung fell. Nvidia reportedly trimmed memory in some Rubin Ultra models amid tight high-end HBM supply. Is scarcity a pricing tailwind or a limit on AI chip shipments and valuations? Repeated drops in 2x long SK hynix products turn the shortage story into a test of expectations.