Negative yields have vanished from the world's corporate bond market as investors brace for monetary tightening.

Every single note in a Bloomberg index tracking the global investment-grade corporate bond market yielded 0 percent or more at Friday's close, calculated using the midpoint between bid and ask prices. It's a dramatic turnaround from August, when more than $1.5 trillion of debt—most of it in Europe—came with a subzero yield.

This milestone marks the end of an era fueled by easy money and extraordinary central-bank policy meant to hold down borrowing costs and stimulate inflation. That was sparked by a combination of the financial crisis and the European debt crisis, followed by the outbreak of the pandemic. Now it's all going in reverse. Bond yields are soaring around the world, and investors are worried that inflation is getting out of control.