BANGKOK, Nov 18, (AP): Asian shares tumbled on Tuesday, with benchmarks in Tokyo and Seoul sinking more than 3%, after Nvidia and other artificial-intelligence -related shares pulled US stocks lower. US futures dropped, with the contract for the S&P 500 down 0.6% while the future for the Dow Jones Industrial Average was down 0.4%. Computer chip giant Nvidia, at the center of the craze over AI, is due to report its earnings on Wednesday.

Worries that stock prices of such companies have shot too high have roiled world markets recently, with big swings in places that rely heavily on trade in computer chips such as South Korea and Taiwan. Also hanging over the markets is the release due Thursday of US employment data that was delayed by the prolonged government shutdown.

Regional markets felt a chill after the yield on 30-year Japanese government bonds surged to 3.31%, reflecting rising risks as Prime Minister Sanae Takaichi prepares to boost government spending and push back the timetable for bringing down Japan's huge national debt. The yen was trading above 155 to the U.S. dollar, near its highest level since February.

On Monday, the yen fell to its lowest level against the euro since 1999, when the unified European currency was launched. Tokyo's Nikkei 225 was down 3% at 48,835.20 by midday, with selling of tech shares leading the decline. Chip maker Tokyo Electron shed 5.4%, while equipment maker Advantest dropped 4.6%. In Seoul, the Kospi fell 3.1% to 3,960.82.

Samsung Electronics dropped 2.9%, while chip maker SK Hynix shed 5.7%. In Taiwan, the Taiex fell 2.3% as TSMC, the world's largest contract chip manufacturer, declined 2.4%. Chinese markets were not immune from heavy selling. Hong Kong's Hang Seng declined 1.5% to 25,997.20, while the Shanghai Composite index slipped 0.6% to 3,949.83. In Australia, the S&P/ASX 200 gave up 2.1% to 8,452.50.