What is Super Bowl Indicator?

Legal Definition
The Super Bowl Indicator is a superstition that says that the stock market's performance in a given year can be predicted based on the outcome of the Super Bowl of that year. It was "discovered" by Leonard Koppett in the '70s when he realized that it had never been wrong, until that point. This pseudo-macroeconomic concept states that if a team from the American Football Conference (AFC) wins, then it will be a bear market (or down market), but if a team from the National Football Conference (NFC) or a team that was in the NFL before the NFL/AFL merger it will be a bull market (up market).
-- Wikipedia