Operating Surplus is an approximate measure of a company’s operating cash flow based on data in the company’s income declaration. Calculated by investigating earnings before deduction of expenses, taxes, devaluation, and amortization. Also known as Earnings Before interest, Taxes, Depreciation and Amortization or operational cash flow. Operating surplus can be a component of importance added and Gross Domestic Product. The term “mixed income” is utilized when operating surplus are not distinguished from income income, for example, in the case of sole proprietorship.