Increasing cost industry in AP Microeconomics

An increasing cost industry is a perfectly competitive industry where expanding output drives up input prices, so firms' cost curves shift upward as new firms enter. The result is an upward-sloping long-run industry supply curve, meaning the long-run equilibrium price rises when demand increases.

What is increasing cost industry?

An increasing cost industry is one where growth makes production more expensive for everyone. As the industry expands, firms compete for the same specialized inputs (think skilled labor, rare materials, or limited land), bidding up their prices. Higher input prices shift every firm's ATC and MC curves upward.

Here's why this matters for the long-run adjustment story in perfect competition. When market demand increases, price rises above ATC and firms earn economic profit. With no barriers to entry, new firms pile in and supply shifts right, pushing price back down. In a constant cost industry, price falls all the way back to its original level. In an increasing cost industry, it can't, because entry itself raised everyone's costs. The new zero-profit price sits at a higher minimum ATC than before. Connect those long-run equilibrium points and you get an upward-sloping long-run supply curve. That's really all this term is: the long-run supply curve has a positive slope because expansion raises costs.

Why increasing cost industry matters in AP® Microeconomics

This term lives in Unit 3 (Production, Cost, and the Perfect Competition Model), Topic 3.7. It supports LO 3.7.A and 3.7.B, which ask you to explain equilibrium and long-run adjustment in perfectly competitive markets using graphs. The standard Topic 3.7 story ends with firms back at zero economic profit, where P = minimum ATC. The increasing/constant/decreasing cost distinction answers the follow-up question the exam loves: zero profit at WHAT price? In an increasing cost industry, the long-run price ends up higher than where it started after a demand increase. This is also where the firm-side cost curves from Topics 3.4-3.5 reconnect with the market-side supply and demand from Unit 2, so it's a genuine bridge concept inside the course.

How increasing cost industry connects across the course

Long-run Equilibrium (Unit 3)

Every point on the long-run industry supply curve is a long-run equilibrium where P = minimum ATC and economic profit is zero. The increasing cost label just tells you those zero-profit points occur at higher and higher prices as the industry grows.

Decreasing cost industry (Unit 3)

The mirror image. In a decreasing cost industry, expansion lowers input costs (maybe suppliers gain economies of scale), so the long-run supply curve slopes downward. Same entry-and-exit logic, opposite cost shift.

Economic profit (Unit 3)

Economic profit is the engine of the whole adjustment. Profit attracts entry, entry expands industry output, and in an increasing cost industry that expansion raises costs until profit hits zero at a higher price than before.

Barriers to Entry (Units 3-4)

The increasing cost mechanism only works because perfect competition has zero barriers to entry (EK PRD-3.A.1). If entry were blocked, profits wouldn't get competed away at all, which is the Unit 4 monopoly story.

Is increasing cost industry on the AP® Microeconomics exam?

This concept shows up in multiple-choice questions about long-run adjustment. A typical stem gives you a demand increase in a perfectly competitive industry and asks what happens to long-run price and quantity. For an increasing cost industry, the answer is that both rise. Questions also run the logic in reverse, describing an outcome and asking you to classify the industry. If the long-run price returns to its original level after adjustment, that's a constant cost industry with a horizontal long-run supply curve, not an increasing cost one. You should be able to identify what would turn a constant cost industry into an increasing cost one (industry expansion starts bidding up scarce input prices). No released FRQ has used this term verbatim, but the side-by-side firm and market graphs it builds on are core FRQ material for Topic 3.7, so know the entry-exit-adjustment story cold.

Increasing cost industry vs Constant cost industry

Both describe perfectly competitive industries adjusting to a demand change through entry and exit. The difference is what entry does to input prices. In a constant cost industry, input prices don't budge, so cost curves stay put and the long-run price returns to its original level (horizontal long-run supply curve). In an increasing cost industry, entry bids up input prices, cost curves shift up, and the new long-run price is permanently higher (upward-sloping long-run supply curve). Quick test on an MCQ: if price ends up back where it started, it's constant cost; if price ends up higher, it's increasing cost.

Key things to remember about increasing cost industry

• An increasing cost industry has an upward-sloping long-run supply curve because expanding industry output bids up the prices of inputs.

• After a demand increase, both the long-run equilibrium price and quantity rise in an increasing cost industry, unlike a constant cost industry where price returns to its original level.

• Firms still end up earning zero economic profit in the long run, but at a higher price, because rising input costs pushed minimum ATC upward.

• The whole mechanism depends on free entry and exit. Profits attract entrants, entrants raise input demand, and input prices rise until profits are competed back to zero.

• Classify the industry by the long-run supply curve's slope: upward means increasing cost, horizontal means constant cost, downward means decreasing cost.

Frequently asked questions about increasing cost industry

What is an increasing cost industry in AP Micro?

It's a perfectly competitive industry where input prices rise as the industry expands, so every firm's cost curves shift up. This makes the long-run industry supply curve slope upward, and long-run equilibrium price rises when demand increases.

Do firms in an increasing cost industry earn long-run economic profit?

No. Just like every perfectly competitive industry, entry continues until economic profit is zero and P = minimum ATC. The difference is that the zero-profit price is higher than it was before, because expansion raised everyone's costs.

What's the difference between an increasing cost industry and a constant cost industry?

In a constant cost industry, expansion doesn't change input prices, so the long-run supply curve is horizontal and price returns to its original level after adjustment. In an increasing cost industry, expansion bids up input prices, so the long-run supply curve slopes upward and price ends up higher.

Why does the long-run supply curve slope upward in an increasing cost industry?

Each point on the curve is a zero-profit long-run equilibrium. As industry output grows, input prices rise and push minimum ATC higher, so each successive equilibrium occurs at a higher price. Connecting those points gives an upward slope.

What could turn a constant cost industry into an increasing cost industry?

Anything that makes the industry's expansion drive up input prices, like relying on a specialized input in limited supply (skilled workers, scarce land, a rare raw material). Once the industry is big enough to bid up those input prices, its long-run supply curve starts sloping upward.