China ’s stock market tumble has presented the government of President Xi Jinping with a searing test of its commitment to overhaul the country’s financial system and open up the state-controlled economy. Building off the work of his predecessors in the last three decades, Mr. Xi has been introducing competition into the banking industry, overhauling state-owned companies and making it easier for foreign investors to buy Chinese stocks. But the pace of reform may slow if the stock market slump persists, or even accelerates. The stock market represents the swirl of social, political and economic forces at play in the reform efforts. Tens of millions of individual investors flocked to stocks in the last year, many of […]