For a counterexample see Brexit. The FTSE 100 went up after Brexit, when other economic indicators were negative, because it primarily contains large multinatio

For a counterexample see Brexit. The FTSE 100 went up after Brexit, when other economic indicators were negative, because it primarily contains large multinationals which are insulated from the local economy. So a stock market index is only correlated with the local economy if there are few multinationals.