Research has pointed to the common tendency to see increased trading activity and higher returns the day before a holiday or a long weekend - a phenomenon known as the holiday effect or the weekend effect.
The idea states that markets tend to see increased trading volume and higher returns the day before a holiday or long weekend, perhaps because investors want to get in their last trades before the stock market closes for the week.

Due to the different time zones and regions where stock exchanges exist across the world, you’ll always find at least one stock market open at any point. However, there is no single stock exchange that is open 24 hours. The U.S. market for example opens at 9.00 a.m and closes at 4.30 p.m ET Monday to Friday.

The forex market’s trading hours are different to that of other markets. Forex market trading times features 24-hour trading, five days a week.

Although the FX market is open 24 hours a day, 5 days a week, the market’s trading times are still important because market conditions are impacted during different sessions or when there is a crossover between trading sessions in 2 different regions. During this time, the market is often more active, and spreads are often tighter as a result. This mainly happens with currency pairs that are associated with both locations of a crossover. For example, the GBP/USD currency pair often experiences greater volumes whilst the European and U.S. sessions overlap for a 4-hour period each day.