Hi Prafulla --

Thanks for reading! As you note, the tradability of these instruments means that one may be able to realize a positive return even if the yield to maturity is negative. I agree it's unlikely we have a 20 year period of persistent deflation, which just serves to underscore how speculative it is to purchase bonds below the zero bound.

That said, it would be possible to have a positive real return and a negative nominal return if that 20 year period were to materialize (not that it's likely to).

All best!

Will