The yields on the longest-dated US government bonds jumped back to levels seen just before Treasury Secretary Scott Bessent shocked markets last month by expanding a buyback program. The 30-year Treasury yields reached 5.27%, the level seen moments before Bessent announced the move on Aug. 19. Bessent's temporary market intervention worked briefly, but a global selloff erased the gains.

The gambit aimed to halt rising yields but failed as market pressures mounted.