分组1 - The iShares Top 20 U.S. Stocks ETF (TOPT) outperformed the S&P 500 index by almost 4% in 2025, but faces concerns in 2026 regarding a potential shift from mega-cap stocks to other large and mid-cap stocks by investors [1] - Geopolitical tensions are also highlighted as a factor that may impact investor sentiment and market dynamics [1] 分组2 - The article emphasizes the importance of unbiased analysis in assisting investors to select effective investment strategies for both short- and long-term horizons [1]