Bonds maturing in 10 years or more have slumped 46% since peaking in March 2020, according to data compiled by Bloomberg. That's just shy of the 49% plunge in US stocks in the aftermath of the dot-com bust at the turn of the century. The rout in 30-year bonds has been even worse, tumbling 53%, nearing the 57% slump in equities during the depths of the financial crisis.

The extent of the losses is a stark reminder of the risk that comes with piling into longer-dated bonds, where prices are the most sensitive to changes in interest rates. That was part of the appeal of the securities as the Federal Reserve spent the better part of a decade cutting borrowing costs to near zero.