Nikkei 225 Breaks 71,000 for First Time, Kospi Tops 9,000, SK Hynix Rises More Than 7% to Record High

TradingKey - During the Asian trading session on June 18, Japanese and South Korean stock markets hit historic milestones. The Nikkei 225 Index closed up 1.65% at 71,053.44 points, crossing the 71,000 mark for the first time. South Korea's KOSPI surged past 9,000 points intraday to close at 9,063.84 points, representing a 2.25% gain. Memory chip giant SK Hynix jumped over 7% to a new record high on news of HBM4E sample shipments.

[Source: TradingView]

The Nikkei Index peaked at 71,398.58 points intraday, refreshing its intraday high for the fourth consecutive trading day. The Topix closed at 4,071.48 points, also hitting a record high. Among its components, SoftBank Group and Tokyo Electron both rallied around 5%, while Kioxia rose 1.36%.

[Source: TradingView]

The KOSPI Index opened higher and accelerated its gains in the afternoon, climbing past 9,000 points for the first time at 12:53 PM before continuing its upward trajectory to close at 9,063.84 points. Since crossing the 8,000-point mark on May 15, the index took just 22 trading days to break through another 1,000-point milestone, bringing its year-to-date gains to over 110%.

SK Hynix announced on the day that it has supplied 12-layer stacked HBM4E samples to key customers. The product is next-generation high-bandwidth memory designed specifically for AI accelerators, offering a single-stack bandwidth of 4.0 TB/s—an increase of approximately 38% over the previous generation—along with improvements in capacity and thermal efficiency. Following the announcement, SK Hynix jumped nearly 5% in early trading, hitting an intraday record high of 2.738 million Korean won, and closed up 7.02% at 2.698 million won, bringing its year-to-date gains to approximately 300%.

This sample delivery comes just three weeks after Samsung Electronics released its first batch of HBM4E samples, highlighting the intensifying technological race between the two companies. Daiwa Securities recently raised its target price for SK Hynix to 3.6 million won while maintaining a "Buy" rating. Samsung Electronics closed at 362,500 won, up 4.62%.

The immediate catalysts for the strength in Japanese and South Korean equities were highly concentrated: the Iranian Foreign Ministry confirmed on the day the formal signing of a memorandum of understanding with the U.S., easing Middle East tensions, driving international oil prices lower, and boosting global risk-on sentiment; meanwhile, continuous foreign capital inflows aligned with domestic institutional buying back in, forming a supportive synergy in capital flows.

In the short term, the robust AI value chain and easing geopolitical tensions will continue to support both markets. However, the Federal Reserve's monetary policy path and global economic growth prospects remain the primary variables capping further upside.