"Now market sentiment has shifted amid worries over massive AI spending, as investors fear those investments will fail to deliver adequate returns," Lin said. Quanta Computer Inc., another AI server supplier, ended down 1.28 percent at NT$309.50 after falling to NT$301.50. "When the Taiex rebounds depends on when the South Korean market stops falling," Lin said. "Investors should also keep a close eye on any signals the U.S. Federal Reserve gives after concluding its policymaking meeting later today." According to the Taiwan Stock Exchange, foreign institutional investors sold a net NT$22.25 billion worth of shares on the main board Wednesday.