If you can handle it, a falling stock market can be a good opportunity for people with long horizons. Broadly diversified, low-cost index funds are a good way to invest in the total stock market. That approach eliminates the risk of holding the wrong specific stocks at the wrong time.If you can handle it, a falling stock market can be a good opportunity for people with long horizons. Broadly diversified, low-cost index funds are a good way to invest in the total stock market. That approach eliminates the risk of holding the wrong specific stocks at the wrong time.