Global shares tumble as tech stocks plunge; Japan, South Korea hit hard

Futures for major U.S. stock indexes pointed lower before Tuesday's opening bell, as technology stocks led a broad selloff across global markets. Japan's Nikkei index fell 3.6 percent, while South Korea's KOSPI dropped 10 percent. European markets also declined, though by smaller margins. The losses follow a sharp downturn in technology shares, which dragged down investor confidence worldwide. Currency traders in Seoul monitored electronic boards showing the exchange rate between the U.S. dollar and the South Korean won, along with the KOSPI and other key indexes. Analysts say the selloff reflects growing uncertainty over the tech sector's outlook, though the exact triggers remain unclear. Markets in Asia and Europe are now bracing for further volatility as U.S. trading opens.