Government bond yields across major economies have risen to multiyear or multidecade highs as the Iran conflict lifts energy prices, investors reassess inflation and monetary policy, and concern over public debt and corporate borrowing intensifies. The US 10-year Treasury yield reached 4.814%, its highest since November 2023, while the UK 10-year yield hit 5.25%, Germany's reached 3.378%, Japan's remained above 3% and Australia's rose to 5.198%. US gross federal debt reached $40.047 trillion on August 18, 2026, after increasing by more than $1 trillion in roughly 150 days, while annual interest payments exceeded $1 trillion and the Congressional Budget Office projected a fiscal 2026 deficit of about $2.1 trillion. Federal Reserve officials, including New York Fed President John Williams and Fed Chairman Kevin Warsh, attributed the rise largely to strong growth and investment in artificial intelligence, data centers and technology, while traders and economists cited stubborn inflation, oil prices above $95 a barrel, fiscal deficits, heavy technology-company bond issuance, a weaker dollar and uncertainty over its reserve-currency status. Higher benchmark yields are raising mortgage and corporate borrowing costs and threatening debt sustainability, equity valuations and emerging-market financing conditions.