In this video, we dive into a portfolio beta calculation problem that you may encounter in finance courses or for CFA studies. The goal is to determine the new portfolio beta after selling two assets—Nero Inc. and Shindo & Co.—and investing the proceeds in a risk-free asset. The video provides a step-by-step breakdown of how to calculate a portfolio's beta, emphasizing the importance of understanding the weighted average method used to compute the portfolio beta, especially when dealing with multiple assets. We begin by reviewing the basic formula for portfolio beta, which is the weighted average of individual asset betas. Then, we apply the formula to a portfolio containing 10 stocks, highlighting how to identify key information such as weights and betas. After reviewing the formula, we move to the core of the problem: finding the beta of the remaining eight stocks in the portfolio. Finally, we calculate the new portfolio beta after reallocating to a risk-free asset, with clear explanations and visualizations to simplify the process. This tutorial is designed to give you a solid understanding of portfolio beta calculations, applicable to real-world investment decisions.