New Delhi, Sep 8 : Shares in Apple have fallen for a second day in a row after reports that Chinese government workers have been banned from using iPhones, the media reported. The firm's stock market valuation has fallen by more than 6 per cent, or almost $200bn (£160bn), in the last two days, the BBC reported. China is the technology giant's third-largest market, accounting for 18 per cent of its total revenue last year. It is also where most of Apple's products are manufactured by its biggest supplier Foxconn. The Wall Street Journal reported that Beijing had ordered Central government agency officials to not bring iPhones into the office or use them for work. The following day, Bloomberg News reported that the ban may also be imposed on workers at state-owned companies and government-backed agencies. The reports came ahead of the launch of the iPhone 15, which is expected to take place on September 12, the BBC reported. There has been no official statement from the Chinese government in response to the reports. Apple has the world's highest stock market valuation, standing at close to $2.8 trillion, the BBC reported. Shares in some of Apple's suppliers have also fallen. Qualcomm, the world's biggest supplier of smartphone chips, dropped by more than 7 per cent on Thursday. Shares in South Korea's SK Hynix were around 4 per cent lower on Friday, the BBC reported. The reports came as tensions between Washington and Beijing remain high. /IANS