As of 11:53 a.m., the Taiex had fallen 1,830.55 points, or 4.40 percent, to 39,772.81, while the bellwether electronics index had fallen 5.08 percent. The last time the Taiex closed below 40,000 points was April 30. Dealers said concerns were running deeper that massive AI investments will not generate satisfactory revenue, prompting investors to trim their holdings of electronic stocks after the Philadelphia Semiconductor Index fell 4.49 percent overnight. Wednesday's plunge followed a more than 2,000-point plunge in the Taiex on Tuesday. Contract chipmaker Taiwan Semiconductor Manufacturing Co. (TSMC), which accounts for over 40 percent of total market value, had fallen 3.29 percent to NT$2,205.00 (US$67.85) as of 11:53 a.m.