South Korean stocks surged Friday as strong U.S. tech earnings revived enthusiasm for artificial-intelligence spending, while the yen weakened further after the Bank of Japan stood pat. Gains in chip stocks led most regional equity markets higher.

Asian chip and technology shares rallied after earnings from major U.S. companies eased investor concerns about the viability of massive data-center investments. The PHLX Semiconductor Sector index jumped 8% Thursday.

Amazon.com reported accelerating growth its cloud-computing business alongside its investment in data centers, cheering investors, while Microsoft delivered blockbuster revenue growth at its cloud-computing unit.

"Stronger results from a leading e-commerce and cloud service provider after the close [Thursday] reinforced the view that AI-related capital expenditure continues to generate robust demand and attractive returns," Commerzbank Research analysts said in a note, referring to Amazon's results.

Meanwhile, the yen weakened against the dollar, surrendering some of its sharp overnight gains after suspected yen-buying intervention by Japanese authorities.

South Korea's Kospi led the region's gains, soaring 17%. The Korea Exchange briefly suspended trading on both the benchmark Kospi and the tech-heavy Kosdaq after the sharp moves. Index heavyweights SK Hynix and Samsung Electronics surged 28% and 22%, respectively.

"Korea remains the most concentrated major market in the world, and the oversupply debate will keep resurfacing every time capacity plans are announced," said Josh Gilbert, lead analyst for Asia Pacific at etoro.

Still, demand for memory chips are not slowing down, and the rebound in the Kospi indicates the market "reading the fundamentals," he added.

Japan's Nikkei Stock Average rose 3.9%. Furukawa Electric climbed 14%, while Advantest, a maker of semiconductor-testing equipment, gained 15%. In Taiwan, TSMC, the world's largest contract chip maker, rose 9.8%. Foxconn Technology Group, the world's largest contract electronics manufacturer, gained 9.6%, while chip designer MediaTek jumped 9.9%.

The surge in semiconductor stocks sent Taiwan's benchmark Taiex 8.0% higher, putting it on track for its best day since April 2025. In China, the tech-heavy ChiNext Price Index gained 5.0%.

In foreign-exchange markets, the yen weakened against the dollar after surging overnight on suspected yen-buying intervention by Japanese authorities.

The dollar was recently 0.8% higher at 160.72 yen, recovering a little after tumbling as much as 3.3% to Y157.96 on Thursday, its lowest intraday level since May 14, according to LSEG data.

Markets are now looking to the Bank of Japan's press conference for signs of increased hawkishness after its decision to keep monetary policy unchanged.

Any surprise intervention by the Japanese government to prop up the yen is likely nothing more than a stopgap measure to buy time, said Kenta Tadaide, chief currency strategist at Daiwa Securities.

"To maximize the impact of currency intervention, monetary policy must align in the same direction," he said.

Still, some see potential for the yen to strengthen.

"For the yen, the story is gradually shifting from rate differentials to capital flows," said Masahiko Loo, senior fixed income strategist at State Street Investment Management.

He noted that the overnight move reinforced the view that authorities are uncomfortable with too much yen weakness.

But State Street is positive on Japanese assets, and expects Japanese stocks to benefit disproportionately if the global tech cycle accelerates. He noted that Japan is a key part of the global supply chain for robotics, automation, semiconductors and industrial infrastructure, where the "next phase" of artificial intelligence development is expected to take place.

As Japan transitions from a place investors fund their investments into a destination for investments, he expects the yen to be increasingly supported by stronger growth, inflation, AI-related investment, rising foreign investments and growing domestic participation.

"The next major yen move may ultimately be higher, not lower," Loo said.

Colin Ng and Megumi Fujikawa contributed to this article