May 2026 will be a month long remembered by investors. South Korea's KOSPI broke the 8,000-point barrier for the first time in history, and semiconductor exports surpassed $30 billion monthly — also for the first time. AI infrastructure investment, U.S.-Iran ceasefire hopes, and yet another earnings beat from Nvidia drove global markets higher. Here's a complete breakdown of what moved markets this month.
1. Three Key Themes of May 2026
① KOSPI 8,000 — A Historic Milestone
On May 15, the KOSPI index crossed 8,000 points for the first time ever. What took two months going from 6,000 to 7,000 took just nine days from 7,000 to 8,000 — the rally is clearly accelerating.
The engine behind the surge was semiconductors. As global tech giants poured capital into AI infrastructure, demand for HBM (High Bandwidth Memory), DRAM, and NAND exploded, lifting Samsung Electronics and SK Hynix earnings well beyond expectations. South Korea's semiconductor exports hit a record $32.8 billion in March, representing roughly 38% of total exports.
Major brokerages revised their KOSPI targets sharply upward: KB Securities raised its target from 7,500 to 10,500, while JP Morgan set its target at 10,000.
② Nvidia's Earnings — Silencing the AI Bubble Debate
Nvidia reported fiscal Q1 FY2027 results on May 20, posting revenue of approximately $78.6 billion — ahead of consensus — with another blowout quarter in its data center segment. This represented roughly 15% growth over the prior quarter's $68.1 billion.
The results delivered a clear answer to persistent market questions about whether AI spending is sustainable. Korean semiconductor, physical AI, and HBM equipment stocks rallied in tandem. Adding to the momentum, reports of U.S. approval for Nvidia's H200 chip exports to ten Chinese tech firms via the U.S.-China summit provided an additional boost.
③ U.S.-Iran Negotiations — A Balancing Act
Geopolitics remained a central variable throughout May. President Trump repeatedly signaled that a ceasefire deal was in its "final stages," prompting oil prices to fall sharply and fueling a relief rally across markets. However, Iranian Supreme Leader Khamenei maintained a firm stance against nuclear concessions, keeping the situation unresolved and markets on edge.
The mechanism matters for investors: rising oil prices stoke inflation fears, weaken rate-cut expectations, and pressure growth stock valuations. The reverse is equally true. Understanding this chain reaction helps explain why Middle East headlines move equity markets so sharply.
2. How Should Investors Read This Market?
The overall direction remains bullish, but several checkpoints deserve attention.
Foreign investor flows have been net negative on KOSPI through May, with cumulative selling exceeding ₩20 trillion. That sounds alarming — but measured against a market cap that has grown to roughly ₩6,300 trillion, the selling ratio is actually lower than February or March. The composition also matters: much of the selling is concentrated in banking and insurance, not the AI-semiconductor names driving the rally.
U.S. interest rate risk is real. On May 19, the 30-year Treasury yield hit its highest level since the financial crisis, triggering tech-led selling. AI growth narratives don't disappear overnight, but sustained high rates make it harder to justify elevated valuations in growth stocks.
MSCI rebalancing is scheduled for after the close on May 29, following the semi-annual index review. Short-term supply-demand swings in affected names are worth monitoring.
The bottom line: the AI earnings cycle is real and powerful, but geopolitical uncertainty and rate volatility remain live risks. Diversification and a long-term horizon remain the most reliable response.