Yahoo Finance analysis indicates that since 1927, in 30 years where the S&P 500 index gained more than 10% in the first half, 23 of those years also recorded positive returns in the second half, a win rate of 77%. Furthermore, in the 11 such years since 1990, the second half consistently achieved positive returns, with a median gain of nearly 10%. Despite strong historical data, analysts still believe that, given the current high inflation and interest rates, a repeat of a 10% gain in the second half should not be fully expected.