Apple world's most valuable company in 2015. 100 leading companies quoted on the stock exchange in 2015 are now worth $16,245 billion, almost as much as US GDP, according to a new survey by PwC. They have almost doubled their stock market capitalisation since 2009 and their value increased by 8% over the course of a year, while the Top 100 companies paid their shareholders (dividends and share buybacks) no less than $689 billion. In total, PwC looked at 53 US companies in the Top 100 in...