The S&P 500, the Nasdaq and the Dow Jones — all hit all-time highs this year, having gained about 12.5%, 16.1% and 8.4%, respectively, so far this year (as of Sept. 25, 2025). But the fourth quarter may see even higher gains as it includes the all-important holiday season.The fourth quarter of the year has actually been the best for the stock market. Over the past three decades, dated back to 1989, the Dow Jones (4.3%), the S&P (3.6%) and the Nasdaq (4.7%) posted gains in the fourth quarter, according to Ke ...