The stock market has spent most of 2025 defying both gravity and logic. Despite persistent geopolitical tensions in Europe and the Middle East, new tariffs, and unease over the timing of the Federal Reserve's policy decisions, the S&P 500 is up roughly 13% year to date as of this writing (Oct. 13). Yet this headline figure hardly captures the full drama beneath the surface.
The year began with roaring optimism, fueled by accelerating investment in artificial intelligence (AI). But the rally hit turbulence in April when President Trump announced his "Liberation Day" tariffs, a move that briefly shook Wall Street's confidence and sent retail investors scrambling. Since bottoming in mid-April, however, the S&P 500 has surged more than 20% -- a powerful rebound that has reignited the bull market.
^SPX data by YCharts
If current momentum holds through the end of the year, 2025 would mark a third consecutive year of double-digit gains. Such a streak is exceedingly rare. Over the past century, the index has posted back-to-back annual gains of 20% or more in only four distinct eras: the 1920s, 1930s, 1950s, and 1990s. Each of those periods created enormous wealth -- but also painful lessons -- reminding investors that history's verdict on sustained rallies is anything but clear.
