What does Contribution to Effective Duration mean?

Contribution to Effective Duration is a number that adds across all bonds or sectors to equal overall portfolio effective duration. It is a way of measuring allocation that takes into account both the market value weight and also the duration risk. If multiplied by a yield shift, it can estimate Contribution to Total Return resulting from that parallel yield shift. It is calculated by multiplying the bond's or sector's duration by its % market value weight.