Glossary term
Convexity
The rate of change of a bond's duration; it makes price gains from falling rates exceed price losses from rising rates.
Convexity measures how a bond's duration itself changes as interest rates move, capturing the curvature in the price-yield relationship. Positive convexity means a bond gains more from a rate fall than it loses from an equal rate rise, a favorable asymmetry. It matters most for long-dated bonds and structured products, where the second-order effect becomes large enough to drive returns. See Duration and Money Temperature 101.