The article discusses how to create the best investment portfolio by using math and statistics to predict stock behavior. It shows that choosing the right mix of stocks and bonds can be turned into a math problem. By using the Markowitz model, researchers developed a model for an optimal investment portfolio with specific legal restrictions. They tested this model with 10 types of stocks and bonds from Kazakhstani companies to find the best mix that balances risk and return. This can help companies and entrepreneurs make smart investment decisions based on the expected income from different securities.