key rate duration

Is this correct: we can sum the portfolio’s key rate durations to get portfolio duration.

Do we just simply sum them up? Or should take the weighted average?

Sum

I think money duration using weighted average.

it does not

I remember it is on level 2.

Key rate durations are already weighted so don’t weight just sum.

However: I think for calculating portfolio duration from the individual durations you have to weight. How else?