1. The S&P 500 has been in a secular bull market since its generational low in March 2009, with large-cap growth and tech-driven momentum stocks dominating returns. 2. Small and mid-cap stocks, along with equal-weighted indices, continue to underperform, reminiscent of the late 1990s market dynamics. 3. Current market sentiment fluctuates rapidly between extremes of greed and fear, contrasting sharply with the more stable optimism of the 1990s bull market.