Managerial Decisions in Competitive Markets Chapter 11 Managerial Decisions in Competitive Markets

Perfect Competition Firms are price-takers Each produces only a very small amount of total market or industry output All firms produce a homogeneous (identical) product Entry into & exit from the market is unrestricted (can easily enter market)

Demand for a Competitive Price-Taker Demand curve is horizontal at price determined by intersection of market demand & supply Perfectly elastic Marginal revenue equals price Demand curve is also marginal revenue curve (D = MR) Can sell all they want at the market price Each additional unit of sales adds to total revenue an amount equal to price

Demand for a Competitive Price-Taking Firm (Figure 11.2) S Price (dollars) D Price (dollars) P0 P0 D = MR Q0 Quantity Quantity Panel A – Market Panel B – Demand curve facing a price-taker

Profit-Maximization in the Short Run In the short run, managers must make two decisions: Produce or shut down? If shut down, produce no output and hires no variable inputs If shut down, firm loses amount equal to TFC If produce, what is the optimal output level? If firm does produce, then how much? Produce amount that maximizes economic profit Profit =

Profit Margin (or Average Profit) Level of output that maximizes total profit occurs at a higher level than the output that maximizes profit margin (& average profit) Managers should ignore profit margin (average profit) when making optimal decisions

Short-Run Output Decision Firm’s manager will produce output where P = MC as long as: TR  TVC or, equivalently, P  AVC If price is less than average variable cost (P  AVC), manager will shut down Produce zero output Lose only total fixed costs Shutdown price is minimum AVC

Profit Maximization: P = $36 (Figure 11.3) Total revenue =$36 x 600 = $21,600 Total cost = $19 x 600 = $11,400

Profit Maximization: P = $36 (Figure 11.4) Panel A: Total revenue & total cost Panel B: Profit curve when P = $36

Short-Run Loss Minimization: P = $10.50 (Figure 11.5) Total cost = $17 x 300 = $5,100 Profit = $3,150 - $5,100 = -$1,950 Total revenue = $10.50 x 300 = $3,150

Irrelevance of Fixed Costs Fixed costs are irrelevant in the production decision Level of fixed cost has no effect on marginal cost or minimum average variable cost Thus no effect on optimal level of output

Summary of Short-Run Output Decision AVC tells whether to produce Shut down if price falls below minimum AVC SMC tells how much to produce If P  minimum AVC, produce output at which P = SMC ATC tells how much profit/loss if produce •

Short-Run Supply Curves For an individual price-taking firm Portion of firms’ marginal cost curve above minimum AVC For prices below minimum AVC, quantity supplied is zero For a competitive industry Horizontal sum of supply curves of all individual firms Always upward sloping

Derivation of Short-Run Supply Curves (Figure 11.6)

Long-Run Profit-Maximizing Equilibrium (Figure 11.7) Profit = ($17 - $12) x 240 = $1,200

Long-Run Competitive Equilibrium All firms are in profit-maximizing equilibrium (P = LMC) Occurs because of entry/exit of firms in/out of industry Market adjusts so P = LMC = LAC

Long-Run Competitive Equilibrium (Figure 11.8)

Long-Run Industry Supply Long-run industry supply curve can be flat (perfectly elastic) or upward sloping Depends on whether constant cost industry or increasing cost industry Economic profit is zero for all points on the long-run industry supply curve for both types of industries

Long-Run Industry Supply Constant cost industry As industry output expands, input prices remain constant, & minimum LAC is unchanged P = minimum LAC, so curve is horizontal (perfectly elastic) Increasing cost industry As industry output expands, input prices rise, & minimum LAC rises Long-run supply price rises & curve is upward sloping

Long-Run Industry Supply for a Constant Cost Industry (Figure 11.9)

Long-Run Industry Supply for an Increasing Cost Industry (Figure 11 Firm’s output

Economic Rent Payment to the owner of a scarce, superior resource in excess of the resource’s opportunity cost In long-run competitive equilibrium firms that employ such resources earn only normal profit Economic profit is zero Potential economic profit is paid to the resource as rent

Economic Rent in Long-Run Competitive Equilibrium (Figure 11.11)

Implementing the Profit-Maximizing Output Decision Step 1: Forecast product price Use statistical techniques from Chapter 7 Step 2: Estimate AVC & SMC • •

Implementing the Profit-Maximizing Output Decision Step 3: Check shutdown rule If P  AVCmin, produce If P < AVCmin, shut down To find AVCmin, substitute Qmin into AVC equation

Implementing the Profit-Maximizing Output Decision Step 4: If P  AVCmin, find output where P = SMC Set forecasted price equal to estimated marginal cost & solve for Q*

Implementing the Profit-Maximizing Output Decision Step 5: Compute profit or loss Profit = TR - TC If P < AVCmin, firm shuts down & profit is -TFC

Profit & Loss at Beau Apparel (Figure 11.13)

Profit & Loss at Beau Apparel (Figure 11.13)

Homework Read Chapter 11 pages 396 – 421 Do Tech probs. 1, 2, 3, 4, 6, 7, 8, 9 Do Applied problems: 1, 6, 7, 8