If interest high, then capital confirm not protected.
If interest low, then capital protected.
Singapore's inflation average 3%pa. SO if whatever investment/FD/SD
is doing below 3%pa, then you are still losing.
Personally I wun do SD. Most SD in the local bank I know
lost.
However you can still make above 11% pa consistently with limited
risk which is what financial institutions are doing, by of course
the interest they make is much higher. We can do too.
PM me if interested.