The primary objective of the research is to offer investors and readers a comprehensive guide in selecting a portfolio that maximizes profits and minimizes risks during the investment process. The portfolio is a collection of various investments held by an investor, including stocks, bonds, securities, real estate, fund certificates, bank deposits, gold, foreign currency, and other investment products. The design of a portfolio depends on an investor’s risk appetite and financial goals. However, the research focuses mainly on stock portfolios. The study utilizes multiple methods to analyze data to assess risk. It is essential to consider various statistical measures, including matrix functions, variance, standard deviation, and variation coefficient. Additionally, an empirical study is conducted using the return on equity (ROEA) dataset collected from three large companies listed in Ho Chi Minh city stock exchange over the time series from 2005 to 2023. This study provides a practical understanding of how investors and readers can apply the methods used to measure risk in real investment situations. The research offers guidance to investors and readers on how to choose portfolio optimization that ensures the appropriate allocation of investments, achieves the desired level of profitability, and minimizes risks. To build a portfolio, investors should focus on three key components: investment types, allocation ratios, and risk tolerance. By considering these factors, they can align portfolios with their investment goals. The chapter discusses four basic portfolio types: risky, safe, income-providing, and balanced, detailing their advantages and disadvantages. This information helps investors make informed decisions when selecting a portfolio that suits their goals and risk appetite.