Rising U.S. 10-year Treasury yields in September 2026 have been propelled primarily by a repricing of Federal Reserve policy expectations toward fewer cuts or potential hikes, alongside an expanding real term premium tied to heavy Treasury issuance, fiscal deficit concerns above 6% of GDP, and corporate borrowing for AI infrastructure. Strong PMI readings, resilient labor data, and oil price volatility linked to geopolitical tensions have reinforced inflation concerns, pushing yields from early-month levels near 4.73% to intraday highs above 5.23% by late September. Market-implied odds reflect trader focus on upcoming PCE inflation and employment releases that could shift rate path expectations, while structural supply-demand imbalances continue to support elevated term premia relative to historical norms.