If two companies have the same amount of net income and total assets how can they have two different return on equity amounts?

The DuPont formula, also known as the strategic profit model, is a common way to break down ROE into three important components. Essentially, ROE will equal net margin multiplied by asset turnover multiplied by financial leverage. Splitting return on equity into three parts makes it easier to understand changes in ROE over time. For example, if the net margin increases, every sale brings in more money, resulting in a higher overall ROE. Similarly, if the asset turnover increases, the firm generates more sales for every dollar of assets owned, again resulting in a higher overall ROE. Finally, increasing financial leverage means that the firm uses more debt financing relative to equity financing. Interest payments to creditors are tax deductible, but dividend payments to shareholders are not. Thus, a higher proportion of debt in the firm's capital structure leads to higher ROE. Financial leverage benefits diminish as the risk of defaulting on interest payments increases. So if the firm takes on too much debt, the cost of debt rises as creditors demand a higher risk premium, and ROE decreases. [2] Increased debt will make a positive contribution to a firm's ROE only if the firms ROA exceeds the interest rate on the debt. [3]

ROE = \frac{Net\ income}{Sales}\times\frac{Sales}{Total\ Assets}\times\frac{Total\ Assets}{Average\ stockholders\ equity}