The yield on the 10-year US Treasury note rose above 4.8% in September, its highest level since October 2023. Markets faced the risk of higher Federal Reserve rates as the US and Iran resumed strikes, extending halted energy supplies from Gulf Cooperation Council countries and pushing up oil and refined-product prices. Multiple FOMC (Federal Reserve rate-setting committee) members, including Chairman Warsh and regional Fed presidents, flagged the possibility of a rate increase this month. Heavy corporate debt issuance also weighed on demand for government securities, with estimates that AI companies raised $1.5 trillion in debt this year limiting primary dealers' allocations. Treasuries additionally came under pressure amid reports that Japan could intervene to restrain a fresh rebound in the yen. The rise in yields continued even after Treasury Secretary Bessent announced increased buybacks of long-term securities.