Stocks tumble as coronavirus fears overpower stimulus efforts

US and European stocks dropped on Thursday as coronavirus fears outweighed stimulus efforts.
US lawmakers approved $8 billion, Chinese finance ministers allocated $16 billion, and the International Monetary Fund earmarked $50 billion to combat the epidemic.
Rate cuts and government cash may not prevent coronavirus from disrupting businesses and supply chains, eroding consumer demand, and weakening global growth.
"Investors have stopped backing riskier assets once again as they lose their optimis