Thailand's stock market and currency have tumbled and the prime minister has canceled an overseas trip amid concerns about long-ailing King Bhumibol Adulyadej's health. His son, the crown prince, returned to Thailand from Germany. The Stock Exchange of Thailand's benchmark fell nearly 7 percent Wednesday afternoon before recovering somewhat for a 4.1 percent loss for the day. Thai stocks have slid daily since Sunday, when the royal palace announced that Bhumibol's condition was unstable, the first time it has used that phrase regarding the king's health. Also Wednesday, the Thai baht fell 1.1 percent to end at 35.76 to a dollar. Bhumibol, 88, is the world's longest reigning monarch. He has spent most of the last decade in a hospital.