India, Aug. 20 -- The S&P 500 had a strong start to 2026. The index gained 10.2% on a total-return basis during the first half of 2026, putting it among a group of years when strong first-half gains were followed by generally positive second-half returns.

History gives investors a reason to stay optimistic. Since 1927, there have been 30 times when the S&P 500 gained at least 10% in the first half of a year. In 23 of those 30 cases, the index also finished the second half with a gain. That means the second-half success rate was about 77%, according to The Motley Fool.

The average historical gain was also strong. In those 30 cases, the median second-half return was about 9%, while the average, or mean, return was about 6%, according to T...