While the markets are open on Monday, banks, schools, and government offices are closed. In past years, with the bond market closed, the stock market has done quite well on Columbus Day. Last year Columbus Day saw a gain in the S&P of over 11%. Many traders will likely recall it was the week prior that the market suffered its multi-day crash. Stats associated with Columbus Day are now a bit skewed thanks to 2008. Below is a chart from 1961 – present that shows Columbus Day performance.
As you can see it has generally been a positive holiday for the market.