The stock returns on Friday tend to be higher than on Monday. Researchers explain it with the fact that on Monday investors tend to be in a bad mood (because of the start of the working week) and therefore interpret all news in a negative way. On the contrary, on Friday investors tend to be in a good mood (because of the approaching weekend) and therefore interpret all news in a positive way. If there are no limits to arbitrage, then rational investors will be able to exploit these return patterns by: