#cfa-level-1 #microeconomics #reading-15-demand-and-supply-analysis-the-firm

Total costs (TC) are the summation of all costs, where costs are classified according to fixed or variable. Total costs increase as the firm expands output and decrease when production is cut. The rate of increase in total costs declines up to a certain output level and, thereafter, accelerates as the firm gets closer to full utilization of capacity. The rate of change in total costs mirrors the rate of change in total variable cost. In Exhibit 13, TC at 5 units is 400—of which 300 is variable cost and 100 is fixed cost. At 10 units, total costs are 1,650, which is the sum of 1,550 in variable cost and 100 in fixed cost.

Total fixed cost (TFC) is the summation of all expenses that do not change when production varies. It can be a sunk or unavoidable cost that a firm has to cover whether it produces anything or not, or it can be a cost that stays the same over a range of production but can change to another constant level when production moves outside of that range. The latter is referred to as a quasi-fixed cost, although it remains categorized as part of TFC. Examples of fixed costs are debt service, real estate lease agreements, and rental contracts. Quasi-fixed cost examples would be certain utilities and administrative salaries that could be avoided or be lower when output is zero but would assume higher constant values over different production ranges. Normal profit is considered to be a fixed cost because it is a return required by investors on their equity capital regardless of output level. At zero output, total costs are always equal to the amount of total fixed cost that is incurred at this production point. In Exhibit 13, total fixed cost remains at 100 throughout the entire production range.

Other fixed costs evolve primarily from investments in such fixed assets as real estate, production facilities, and equipment. As a firm grows in size, fixed asset expansion occurs along with a related increase in fixed cost. However, fixed cost cannot be arbitrarily cut when production declines. Regardless of the volume of output, an investment in a given level of fixed assets locks the firm into a certain amount of fixed cost that is used to finance the physical capital base, technology, and other capital assets. When a firm downsizes, the last expense to be cut is usually fixed cost.

Total variable cost (TVC), which is the summation of all variable expenses, has a direct relationship with quantity. When quantity increases, total variable cost increases; total variable cost declines when quantity decreases. At zero production, total variable cost is always zero. Variable cost examples are payments for labor, raw materials, and supplies. As indicated above, total costs mirror total variable cost, with the difference being a constant fixed cost. The change in total variable cost (which defines marginal cost) declines up to a certain output point and then increases as production approaches capacity limits. In Exhibit 13, total variable cost increases with an increase in quantity. However, the change from 1 to 2 units is 25, calculated as (75 – 50); the change from 9 to 10 units is 350, calculated as (1,550 – 1,200).

Another approach to calculating total variable cost is to determine the variable cost per unit of output and multiply this cost figure by the number of production units. Per unit variable cost is the cost of producing each unit exclusive of any fixed cost allocation to production units. One can assign variable cost individually to units or derive an average variable cost per unit.

Whenever a firm initiates a downsizing, retrenchment, or defensive strategy, variable cost is the first to be considered for reduction given its variability with output. However, variable cost is reducible only so far because all firms have to maintain a minimum amount of labor and other variable resources to function effectively.


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