# Optimization

Optimization can be used to:<ul><li>lower the risk of a portfolio while preserving its expected return</li><li>maximize the expected return of a portfolio while preserving its risk</li></ul>Optimization depends on a set of <span style="font-weight: bold;">assumptions</span>. Portfolio Lab provides a set of default assumptions based on a simple forward model. You should review the assumptions and change them if needed to match your views and constraints.