How AI Chip Mania and a US-Iran Ceasefire Propelled Asian Stocks to Record Highs in May 2026

The AI Semiconductor Boom Rewrites the Record Books

The dominant engine of the rally was an AI-driven surge in demand for high-bandwidth memory (HBM) and advanced logic chips. By early May 2026, the Philadelphia Semiconductor Index had already surged 55% year-to-date, setting a blistering pace that Asian markets would follow .

The Trillion-Dollar Memory Chip Club

On May 27, South Korea's SK Hynix saw its stock surge as much as 14.9%, pushing its market capitalization to approximately $1.08 trillion and making it the world's 12th most valuable company . This milestone came just weeks after Samsung Electronics crossed the $1 trillion threshold on May 6, the same day the KOSPI index first breached the 7,000-point level . Micron Technology joined them a day earlier on May 26, meaning all three of the world's major memory chipmakers were simultaneously valued above $1 trillion for the first time .

The speed of the revaluation was breathtaking. SK Hynix's stock had already gained more than 200% year-to-date and 274% across all of 2025, driven by orders for HBM chips essential to AI data centers . Just 16 months prior, the company was valued at under $100 billion .

Taiwan's TAIEX Surges Past 42,000

Taiwan's market rode the same wave, with its benchmark TAIEX posting its largest-ever single-day point gain on May 4, surging 1,778.51 points to close above 40,000 for the first time . The rally was led by TSMC, which accounts for over 40% of the TAIEX's total market value . The index continued its ascent, crossing 42,000 by May 12, with its year-to-date gain exceeding 50% by late May . The gains were so rapid that the KOSPI briefly triggered a rare "sidecar" trading curb on May 6 to cool volatility .

A Global, Tech-Concentrated Rally

The AI mania was not contained to a single market. Japanese tech and chip-linked shares pushed the Nikkei to multi-decade highs, while the broader MSCI Asia Pacific Index jumped 2.3% in a single session on May 5 as investors rushed into semiconductor names . South Korea's retail "ant" investors also swarmed into the market, buying up shares of Samsung and SK Hynix and pushing the KOSPI past 7,700 in mid-May .

The Geopolitical Catalyst: A Fragile Ceasefire Eases Oil Fears

While the AI trade provided the thrust, a late-month geopolitical development added fresh fuel. On May 29, US and Iranian negotiators reached a tentative 60-day ceasefire extension, pending approval from President Donald Trump . The news reversed a sluggish start to the trading day on Wall Street and sent Asian markets surging .

The most immediate effect was on crude oil. Brent crude prices, which had been elevated by the conflict and the effective closure of the Strait of Hormuz, dropped nearly 19% in May alone in their worst monthly decline since 2020, with WTI hovering around $87 per barrel . The de-escalation directly eased energy cost fears that had been weighing on manufacturing-heavy Asian economies and encouraged some rotation into non-tech sectors .

Broader Market Implications and Concentration Risks

Despite the celebratory mood, the rally's narrow foundation was a point of concern. South Korea became the first country outside the United States to simultaneously host two trillion-dollar companies, underscoring its central role in the AI supply chain . However, analysts noted that the gains were heavily concentrated in the semiconductor sector. In Taiwan, TSMC alone accounted for over 60% of the market's 2026 growth, while traditional industries like textiles and raw materials faced downturns . As one report put it, the "ballooning mania for computer-chip stocks" left investors questioning whether the run was "another valuation bubble likely to pop" .

A BNP Paribas analyst captured the sentiment by noting Asian equities were "back in full gallop after their March stumble," but this gallop was largely confined to a handful of AI-linked giants .

Outlook: How Long Can the AI Chip Rally Last?

The market's pricing action in May 2026 reflected a strong conviction that AI chip demand is a multi-year, structural shift rather than a cyclical upswing. UBS reportedly stated after SK Hynix's milestone that its market cap could "more than double over the next 12 months," reflecting aggressive long-term growth assumptions .

While specific 2027–2028 demand forecasts are not available in current reports, the market's actions speak clearly: the simultaneous revaluation of all three global memory leaders within a single month suggests that investors are applying AI-driven growth multiples that extend well beyond the current earnings cycle. The critical test will be whether end-user AI adoption can scale fast enough to justify the trillion-dollar bets placed on the hardware that powers it.