This study empirically analyzes the impact of financing methods on a company’s capital structure. To achieve this, companies listed on the Tehran Stock Exchange from 2006 to 2009 were categorized into two groups: those with high leverage and those with high stock issuance. Their performance was then evaluated using the Capital Asset Pricing Model (CAPM) and capital structure theories. By applying CAPM, we calculated the risks and expected returns for both groups and compared them to each other and the market. Statistical tests, including F-Levene and Student’s t-test, were used to validate the assumptions. The results indicate that companies financing through stock issuance exhibited lower risk and higher returns. Consequently, this group demonstrated better performance against systematic risk and created more value for shareholders.