The steel industry holds a pivotal position in Iran's economic structure, and fluctuations in the stock prices of major companies in this sector, including Foolad Mobarakeh, can have extensive effects on macroeconomic capital market indicators. In recent years, examining systematic risk and how the stock returns of these companies react to market changes has become doubly important, especially for institutional investors and fundamental analysts. This research aims to measure the extent of dependence of Foolad Mobarakeh's stock returns on the movements of the total index and to evaluate the stock's position from a systematic risk perspective. It analyzes data related to sixteen quarterly periods from 01/07/1400 to 31/06/1404 (Iranian calendar). In this study, first, the returns related to the stock and the total index were extracted, and then the beta coefficient, as the main measure of systematic risk, was calculated by the ratio of the covariance of the stock's and market's returns to the variance of the market's returns. The estimates indicate that the beta coefficient is 1.28, signifying a volatile reaction of the stock to market fluctuations and a higher-than-average market risk. This result suggests that during the studied period, Foolad Mobarakeh's stock exhibited riskier behavior compared to the market index and may not be a suitable option for portfolios, particularly for investors who prefer to bear lower risk. Furthermore, the trend analysis of returns shows that the stock's fluctuations in some periods were influenced by industry variables and the company's fundamental factors, and did not necessarily move in sync with the general market trend. These findings collectively highlight the importance of simultaneously considering industry characteristics and the behavior of the total index when analyzing the risk of large and influential stocks in the capital market.