The switch in indices of the Thrift Savings Plan, essentially the 401(k) plan for federal employees, will take place next year.Sound unimportant?The Thrift Board made one of the most consequential investment decisions of the year, and it will undoubtedly affect allocations of other investment managers, in America and perhaps elsewhere. In short, this move will be a blow to China’s failing equity markets, delivered at the worst possible moment for Beijing.