SHANGHAI, July 28 (Reuters) - China’s central bank on Wednesday dragged its official yuan midpoint to the weakest level in more than three months to reflect broad weakness in the spot market a day earlier following a sharp sell-off in Chinese stocks. The People’s Bank of China (PBOC) set the midpoint at 6.4929 yuan per U.S. dollar prior to market open, 195 pips or 0.3%, weaker than the previous fix of 6.4734. It was the weakest since April 23. Wednesday’s official guidance largely matched market forecasts, and it was 5 pips stronger than Reuters’ estimate of 6.4934. (Reporting by Winni Zhou and Andrew Galbraith; Editing by Christopher Cushing) Our Standards: The Thomson Reuters Trust Principles.