Yahoo Finance analysis indicates that despite the S&P 500 reaching 27 all-time highs so far in 2026 and rising about 13% year-to-date, historical data from 1988 to 2023 shows the index gained an average of 13.4% in the 12 months following a record close, compared to an average of 11.9% over any random 12-month period. This suggests that new highs often act as a catalyst for future gains, rather than signaling an imminent decline.