ylamidon

It is composed of $\delta$ risky assets and $\gamma$ risk-free assets.

renders as

It is composed of $\delta$ risky assets and $\gamma$ risk-free assets.

ylamidon

A workaround is to go the next line before $\delta$

It is composed of 
$\delta$ risky assets and $\gamma$ risk-free assets.

renders as

It is composed of $\delta$ risky assets and $\gamma$ risk-free assets.