The losses are particularly pronounced given the historically low levels of yields since the Fed pulled its policy rate to near zero last year.
This environment makes bond prices, particularly at the longer end of the maturity spectrum, far more sensitive to interest rate fluctuations
Longer-term bonds are also more susceptible to changes in the inflation outlook
The Fed has not yet expressed concern about the rise in yields, but it has set parameters for the kind of market moves that would worry policymakers.
FT 1 April 2021