Percentage Gain/Loss When Buying on Closing on Friday and Selling on Monday Opening 1982 to end of 2024- Assumes blind trading where the closing price is bought and opening price is sold on
This figure would be highly influenced by economic or otherwise news over the weekend, however it can be seen that over time the line of best fit is slightly above zero, so on average money would be made using this trading strategy, however gains could massively increased by using technical indicators and your own judgement to adjust investments.
Percentage Change Between Friday Low and Following Monday High 1982 to end of 2024- This assumes perfect trading where the lowest price on Friday is bought on and the highest price on Monday is sold on.
However unrealistic this would be to attempt in reality, using the technical indicators in the 'Graphs' section on this site it can be approximated where trading should be done so that stocks can be bought at the low and sold at the high. It can be seen that the line of best fit is firmly above zero at just below 1% gains over the weekend with it trending relatively flat over time since 1982.
Percentage Change from the Monday Open to the Friday Close of the Same Week 1982 to end of 2024- Assuming that stock is bought on the first opening price on Monday and held until Friday where it is sold on the closing price, it can be seen by the trend line that the return would be noticeable over time, being around 0.15% each week. This suggests consistent and compounded growth over the years. The trend line seems to suggest that these returns have been decreasing, as in 1982, the return was approximately 0.21%, however this is probably because the trend line is includes the large and sudden losses seen in the historic recessions such as the dotcom bubble burst, 2008 GFC, Covid-19 pandemic, etc. These recessions however short (with rebounds following), contribute large negatives to the average and sway the best-fit line to show a downtrend, when the S&P 500 continues to grow.
Percentage Change from Monday Low to Friday High of the Same Week 1982 to end of 2024- This assumes perfect trading where the lowest price is bought on Monday is bought on the highest price is sold on on Friday.
Although this is unrealistic it bring returns up to 1.3% at the end of 2024 down from 1.45% in 1982 although this decrease is probably due to the reasons mentioned above. This further evidences the contention that gains in the S&P 500 are on average increasing and growth continues. With the help of other technical indicators like on the 'Graphs' section intelligent trading decisions can be made and investments can be successful in this index.