Silence cost is the homonym of sunk cost, which refers to the expenses that occurred in the past but have nothing to do with the current decision.

it means that irrecoverable expenditure has occurred, which exists in various forms, such as time, money and energy. It is often compared with variable costs, which can be changed, while sunk costs cannot be changed. Sunken cost is a kind of historical cost, which is uncontrollable for existing decision-making, and will greatly affect people's behavior and decision-making. In this sense, the interference of sunk cost should be excluded when making investment decisions. For an enterprise, sunk cost is the expenditure that the enterprise has paid cash in the previous business activities and amortized the cost during the business period. Therefore, fixed assets, intangible assets and deferred assets are all sunk costs of enterprises.

in terms of cost traceability, sunk cost can be either direct cost or indirect cost. If sunk costs can be traced back to individual products or departments, they are direct costs; If it is caused by several products or departments, it is an indirect cost. From the form of cost, sunk cost can be fixed cost or variable cost. When an enterprise cancels a department or stops the production of a product, the sunk cost usually includes both fixed costs such as machinery and equipment, as well as variable costs such as raw materials and spare parts. In general, fixed costs are more likely to sink than variable costs.