Risk aversion
= Risk aversion
{wiki}
For increasing <expected utility> preferences, an investor is risk-averse when a sure mean is at least as desirable as the corresponding lottery. A concave <utility function> gives this preference by the <Jensen inequality>; a strictly concave utility gives strict preference for nondegenerate risks. Local risk aversion is measured by $-U''/U'$ and its relative counterpart $-WU''/U'$.