Yahoo Finance, citing analysis from Carson Investment Research, indicates that after the S&P 500's nearly 3% rise in August, historical trends suggest the index is poised for average positive returns in September and the final four months of the year. This analysis is based on 11 years between 1945 and 2017 where both August and year-to-date performance were positive, with an average September return of 1% and an average return of 5.6% for the four months leading up to year-end. August's gains were primarily driven by falling oil prices and strong corporate earnings, with the Magnificent Seven tech stocks performing exceptionally well, showing an earnings growth rate exceeding 118%.