Such a very unusual situation
Never in history before 2015 were there negative interest rates.
If inflation is at 5% it is normal for bondholders to demand a yield of at least 7%. That way they get 2% real return for the sacrifice of lending out their money, postponing consumption.
It’s been crazy and idiosyncratic for bondholders to get negative real returns.
It’s crazy and idiotic that European central banks still have interest rates below zero as inflation is raging.