A collection of financial assets and securities is referred to as aportfolio. Most individuals and institutions invest in a portfolio, making portfolio risk analysis an integral part of the field of finance. Just like stand-alone assets and securities, portfolios are also exposed to risk.Portfolio riskrefers to the possibility that an investment portfolio will not generate the investor's expected rate of return.

Analyzing portfolio risk and return involves the understanding of expected returns from a portfolio.

Consider the following case:

Andre is an amateur investor who holds a small portfolio consisting of only four stocks. The stock holdings in his portfolio are shown in the following table: