A Vanguard index fund or ETF is reportedly outperforming the S&P 500 in 2026. The fund's performance is being attributed to various factors, including its momentum-driven strategy and low costs, although the specific characteristics and history of the fund's success are not entirely clear. The fund has apparently been outperforming the S&P 500 for an extended period, with some reports suggesting it has done so for over 20 years.