SG Morning Brief | SOX Plunges 8% as AI Memory Rout Deepens, Nasdaq -2.2%; Micron Reports Tonight

US OvernightThe Nasdaq tumbled 2.21% to 25,587.04 and the S&P 500 fell 1.44% to 7,365.47, both closing at two-week lows. The Dow slipped 0.09% to 51,665.49. The Russell 2000 gained 0.83%, extending its outperformance. The VIX surged to 19.52. The US session extended the global chip rout that began during Tuesday's Asian session, when the KOSPI plunged 10% after reports that SK Hynix is repurposing an HBM4 production line for general-purpose DRAM. That panic carried straight into New York, where the SOX cratered 7.9%. Consumer staples led the S&P with a 1.8% gain as six of eleven sectors finished positive. Markets are now pricing two Fed rate hikes by December, up from one just two weeks ago. Investing.com noted the Magnificent Seven has turned negative year-to-date.Key MoversSOX -8%: Micron -13% / SanDisk -13% / Marvell -9% — The semiconductor rout was indiscriminate. Micron fell 13.18% to $1,051.77, a day before its Q3 earnings report. SanDisk dropped 13%. Marvell sank over 9%, Qualcomm fell 8.59%, ARM 8.41%, and Nvidia 2.74%. The catalyst was the SK Hynix report suggesting AI memory demand may be peaking faster than expected — a direct challenge to the supercycle thesis that powered the sector's 80%+ YTD rally.IBM (IBM) +5% — IBM bucked the selloff entirely, rising 5% as investors rotated into value tech with lower AI exposure. Microsoft also gained 2.5% and Amazon rose 1.7%, suggesting the market is differentiating between AI infrastructure (sold) and AI platform/cloud (held).SpaceX (SPCX) +1% — SpaceX gained nearly 1%, snapping its three-day losing streak. The stock remains volatile, trading near $155, roughly 15% above its $135 IPO price but well below its $193 post-IPO peak.After hours, Cerebras (CBRS) -10% — The AI chipmaker and Nvidia rival fell as much as 10% after reporting quarterly results that disappointed investors. The stock had already declined from its $311 IPO-day close in May to the low $200s.SGX PreviewThe STI was near 5,070 recently. DBS is near S$62.18 and UOB near S$37.91. Yesterday's global chip rout will continue to pressure Venture Corp and local semiconductor names today. However, the Russell 2000 hitting new highs and consumer staples leading suggest the real economy is healthy — which supports Singapore banks. Tonight's Micron earnings are the key catalyst: a beat could stabilize the memory sector; a miss could extend the rout into a full correction.Asia Pre-MarketThe key question for today's Asian session is whether yesterday's KOSPI crash has flushed enough positioning or whether more deleveraging lies ahead. SK Hynix and Samsung are the stocks to watch at Seoul's open. If they stabilize, the worst may be over. If selling resumes, the contagion extends further into global chip names ahead of tonight's Micron report.Today's US Earnings and Economic CalendarEventTime (ET)Time (UTC+8)Durable Goods (May)8:30 AM8:30 PMCompanyTimingMicron (MU)Post-mktFedEx (FDX)Post-mktThursday: Core PCE (May). Friday: Michigan Consumer Sentiment.Earnings Spotlight: Micron (MU) — The most consequential chip earnings report since Broadcom's miss three weeks ago. Micron reports fiscal Q3 after the close, having lost 13% today and roughly 25% from its all-time high. The SK Hynix report that HBM4 capacity is being redirected to general DRAM directly challenges Micron's thesis of structural HBM scarcity. If Micron's results confirm that AI memory demand remains robust with pricing power intact, the selloff reverses. If guidance flags any softening in HBM orders or pricing, the correction deepens and the trillion-dollar memory valuations face a repricing.One More ThingThe KOSPI's 10% crash is this cycle's canary in the coal mine. South Korea's market had rallied 90% in 2026, almost entirely on the AI memory trade — SK Hynix and Samsung together make up half the index. When one report about a single production line being repurposed from HBM4 to general DRAM can wipe 10% off an entire country's stock market, it tells you how concentrated and fragile the positioning has become. Tonight, Micron either confirms or denies the demand slowdown. The answer will move trillions.This briefing is for informational purposes only and does not constitute investment advice.