Yields on Japanese government bonds have experienced notable fluctuations, with several maturities reaching multi-decade highs in mid-2025. The 10-year Japanese Government Bond (JGB) yield climbed to approximately 1.595% on July 15, marking its highest level since October 2008 amid concerns over fiscal spending ahead of an upper house election. The 20-year JGB yield rose to 2.65%, its highest since 1999, while the 30-year yield reached an all-time high near 3.2%, the highest since issuance began in 1999. The 40-year bond yield also surged, approaching its highest level since its debut in 2007, with levels around 3.39%. After peaking, yields showed some volatility, with the 30-year yield fluctuating between 3.05% and 3.12% and the 10-year yield moving between 1.53% and 1.61% in late July and early August. Shorter maturities such as the 2-year and 5-year bonds also saw increases, with the 2-year yield rising to around 0.83% and the 5-year yield near 1.07%. The heightened yields reflect market reactions to Japan's fiscal outlook and government bond demand, including a 2-year bond auction that drew the highest demand since October 2024, with a bid-to-cover ratio of 4.47 and a slight dip in yields to 0.82%. Overall, Japan's long-term government bond yields have surged to levels not seen in over a decade, signaling shifts in investor sentiment and fiscal policy expectations.