The answer is yes. On average the index has seen the biggest gains in the first 30 minutes of trading, or an average gain of 0.1% since June 1 in early trading. The second best intraday gain, an average of 0.08%, came in the final hour of each day’s session.
Bespoke found that, on days when the index has closed higher, it averaged a gain of 0.5% in the first 30 minutes and a gain of less than 0.2% in the last hour of the session.
However, on days when the S&P 500 ended down, the average decline was about 0.3% in the early trading, while trading was flat in the final hour.
The weakest times for trading were mid morning and mid afternoon. On average, since June 1 the S&P 500 index has declined 0.03% between 10 a.m. and 11 a.m. and between 2 p.m. and 3 p.m., the results showed.
So one could say that Bespoke’s results suggest to traders: don’t be late, don’t quit early and go ahead a take those coffee breaks.