If you bought Bovespa on Thursday and sold on Friday every week since 2003, you would be rich (if you compounded). We know this. If one was to follow such a strategy, in real-time, would it make money?
In the following strategy an investor would buy at the Close of the “optimal” day that performed best in the 5 past years. She would buy on this day (sell on the next close) for 6 months. At the end of 6 months she would re-optimize, find the “optimal” day of the past 5 years from the current date and follow it for another 6 months. So here is a walk-forward back-test that shows how she would do.
Results are NOT compounded (hence the huge difference). Initial Capital: $100,000 – Profit: $127,438.7