The global bond market just flashed a warning signal that hasn’t appeared in nearly 20 years. Government debt yields across every major economy surged in unison on September 1, sending the Bloomberg gauge of global government debt yields to 3.72%, its highest reading since mid-2008.
The numbers behind the selloff
The 10-year US Treasury yield climbed to roughly 4.79%, its highest mark since January 2025. Japan’s 10-year government bond yield crossed 3% for the first time since 1996, a 30-year high. The UK’s 10-year gilt yields hit approximately 5.234%, a level last seen during the 2008 financial crisis. Thirty-year gilts reached territory not visited since 1998. German 10-year Bund yields touched around 3.34%, their highest since 2011.
Oil, Iran, and the inflation problem that won’t quit
Two forces are driving the rout. The first is oil. Intensifying US-Iran tensions have rattled energy markets, particularly around the Strait of Hormuz, the narrow waterway through which roughly a fifth of the world’s oil supply passes daily.
