The stock-bond relationship is showing a rare pattern: The 2-month correlation between US equities and the 10-year Treasury yield is down to -0.70, the lowest since 1999. In other words, over the last 2 months, stocks and the 10-year Treasury yield have moved in opposite directions by the largest extent this century. At the start of 2026, a positive correlation of 0.40 was observed, near the highest since 2023. Additionally, the 30-day correlation is down to -0.68, also the lowest in 27 years. Not even the 2022 bear market saw such a negative correlation, as the 10-year yield rose, driven by elevated inflation and Fed rate hikes, while stocks fell. Bond markets are incredibly important right now.