• The weekend effect is a phenomenon in the financial markets in which stock returns on Mondays are often significantly lower than on the immediately preceding Friday.

  • While the cause of the weekend effect is debated, the trading behavior of individual investors appears to be at least one contributing factor to this pattern.
  • Some theories attempting to explain the weekend effect point to a tendency for companies to release bad news on the Friday after markets close, which then lowers stock prices on Monday.