SoftBank's Son admits mistakes after Vision Fund's $8.9 billion loss

SoftBankplunged to its first quarterly loss in 14 years on Wednesday, dragged down by an $8.9 billion hit at its giant Vision Fund, as CEO Masayoshi Son admitted poor investment judgment and turning a blind eye to problems at startup WeWork.The scale of the loss shows the risks in Son's strategy ofsplashing out big on cash-burning startups.WeWork's spectacular flame-out this year has sparked questions about Son's judgment in backing unconventional tech founders such as WeWork's Adam Neumann.