According to @KobeissiLetter, the S&P 500 closed 2025 up 16.6%, marking a third consecutive year of double-digit gains, source: @KobeissiLetter, X, December 31, 2025. For crypto, BTC traders often monitor U.S. equity momentum because research has documented time-varying positive correlations between BTC and U.S. stocks, supporting risk-on cross-asset models, source: Coin Metrics Research, State of the Network.