Some helpful explanations :
Return on investment, or ROI, is the most common profitability ratio. There are several ways to determine ROI, but the most frequently used method is to divide net profit by total assets. So if your net profit is $100,000 and your total assets are $300,000, your ROI would be .33 or 33 percent.
Return on investment isn’t necessarily the same as profit. ROI deals with the money you invest in the company and the return you realize on that money based on the net profit of the business. Profit, on the other hand, measures the performance of the business. Don’t confuse ROI with the return on the owner’s equity. This is an entirely different item as well. Only in sole proprietorships does equity equal the total investment or assets of the business.