Japan's government bond (JGB) yield curve steepened Monday as investors sold long-dated securities amid thin liquidity and fiscal year-end adjustments, according to State Street's Masahiko Loo. The 30-year JGB yield surged 5 basis points to 3.75%, while the two-year yield dipped 1.5 bps to 1.36%, reflecting heightened volatility in superlong-duration bonds. JPMorgan's analysts cited rising inflation fears and Middle East oil price shocks as catalysts, noting increased sensitivity to duration risk. Two-year yields held steady at 1.375%, but 10-year yields spiked 1.5 bps to 2.385%, matching a February 1999 high. Loo emphasized JGBs are nearing fair value, with markets pricing a 70% chance of a April Bank of Japan rate hike and a terminal rate near 1.9%.