How prices and profit allocate resources

The rationing, signalling and incentive functions of the price mechanism watched in one market: a supply shock, the price spike that rations buyers and creates profit, the supply response that follows, and the overshoot. Then the case for and against leaving allocation to prices. Through the cocoa boom and bust of 2024 to 2026.

The cocoa boom and bust.

Two bad harvests in Ivory Coast and Ghana, which grow about 60% of the world’s cocoa, took the price from under $4,000 a tonne in 2023 to more than $12,000 in December 2024: two and a half times the previous record. Chocolate bars shrank, prices rose, and manufacturers cut the cocoa content of their recipes. European cocoa grindings fell about 8% in a year.

Farmers who had been paid a fraction of the old price now had every reason to tend, prune and replant. Ghana’s 2025/26 harvest came in at 750,000 tonnes, up 26% on the year before; Ivory Coast shipped 20% more to its ports. By March 2026 the price was around $3,000 and beans were piling up unsold at the docks. The World Bank forecast a halving of the average price in 2026.

No one organised this. How does a price do the work of a planner?

Source: ICE cocoa futures reported by Barchart, 16 June 2026; Ghana Cocoa Board figures reported 5 August 2026; World Bank Commodity Markets Outlook, April 2026.

The price mechanism and the profit motive.

The price mechanism is the way prices, set by demand and supply, decide what is produced, how and for whom, without any central direction. It has three functions:

1. Rationing. When a good is scarce its price rises, and buyers who value it least drop out. The good goes to those willing and able to pay.
2. Signalling. A rising price tells producers that buyers want more; a falling price tells them to make less. Prices carry information nobody has in full.
3. Incentive. A higher price means higher profit, which draws resources into the market: existing firms expand and new ones enter. Losses push resources out.

Together these produce consumer sovereignty: spending decisions by consumers, through prices and profits, direct what the economy produces.

Economists distinguish the short run, when supply can barely respond, from the long run, when new capacity and new entrants arrive. The price overshoots in the short run and settles in the long run.

Think first

In December 2024 cocoa cost more than $12,000 a tonne, two and a half times its previous record. By March 2026 it was about $3,000.

Nobody planned the fall. No government told farmers to grow more or shoppers to buy less.

What did the job?

The price did it. At $12,000 chocolate makers shrank bars and used less cocoa, farmers tended and replanted trees and new producers entered, and within eighteen months the shortage was a glut. That is the price mechanism allocating resources.

Step by step

1. Start with the cocoa market in balance. Demand **D** from chocolate makers and supply **S1** from farmers cross at $4,000 a tonne and Q1. Supply is drawn steep because cocoa trees take four or five years to bear fruit: in the short run farmers can only harvest what is already growing.

   Check: At the equilibrium price of $4,000 a tonne, which is true?

   Equilibrium is where the two curves cross: buyers can buy all they want at that price and sellers can sell all they want. Nothing pushes the price up or down.

2. Then two failed harvests. Supply shifts left to **S2**. At $4,000 there is now excess demand: buyers want Q1 but farmers have only a fraction of it. Buyers bid against each other and the price rises until the market clears at **E2**: $10,000 a tonne and Q2. The price has done its first job: it has found a level at which the scarce beans are all allocated.

   Check: A disease and drought ruin the West African harvest. On the diagram this is:

   The harvest failure changes how much farmers can supply at any given price, so the whole supply curve moves left.

3. Rationing. The move from E1 to E2 is a movement along the demand curve. At $10,000 the buyers who value cocoa least drop out: budget chocolate makers cut cocoa content, shrink bars or switch to compound coatings. The beans go to those willing to pay. Nobody queues and nobody issues coupons; the price does the sorting.

   Check: Between E1 and E2 the quantity bought falls from Q1 to Q2. Who stops buying, and why?

   A rising price rations the good by willingness to pay. Those with the cheapest alternatives drop out first; those who must have cocoa pay up.

4. Signalling and incentive. The price has risen two and a half times: a loud signal that the world wants more cocoa. The shaded area is the profit farmers now make above their old costs. That profit is the incentive: Ivorian and Ghanaian farmers prune, treat disease and replant; growers in Ecuador, Nigeria and Brazil expand; chocolate makers invest in substitutes. Resources move towards cocoa from other uses.

   Teacher tip: Students write “the price rises so supply increases”. Be precise: the price rise causes a movement along S2 at once, and the profit causes a shift to S3 later, as new trees and new producers arrive. Different things, different timescales.

   Check: At $10,000 a tonne a farmer whose costs are $3,000 a tonne makes $7,000 of profit on each tonne. Which function of the price mechanism is this?

   High profit is the reward that pulls land, labour and capital into a market: existing farmers tend and replant, new producers enter.

5. Eighteen months on, the response arrives. Supply shifts right to **S3**: more trees, better tended, new countries. The price falls to **E3**, $3,000, below where it began, and beans pile up at the ports. Resources have been pulled into cocoa, and now the low price and losses will push the marginal ones out again. The price works in both directions.

   Check: By 2026 the new plantings bear fruit and supply shifts to S3. The price falls to $3,000, below where it started. Why does the market overshoot?

   Trees planted in 2024 produce in 2026 whatever the price is then. Meanwhile high prices cut demand. The combination overshoots; the cobweb pattern of agricultural markets.

6. Scale this up. Across millions of markets, prices rise where consumers want more and fall where they want less; profits attract resources into the first and losses push them out of the second. No committee decides how many cocoa trees, electricians or phone screens the world needs. That is the case for the free market: it uses knowledge spread across everyone, and it adapts without being told.

   Check: Which statement best describes how prices and profit allocate resources across a whole economy?

   Millions of separate decisions, coordinated by prices, move land, labour and capital towards what people are willing to pay for: consumer sovereignty.

What your diagram must show

• Axes labelled price and quantity
• D sloping down and S1 sloping up, with E1 marked and read across and down
• S2 to the left of S1, with the shift shown, and E2 at a higher price and lower quantity
• S3 to the right, with the shift shown, and E3 at a lower price and higher quantity
• Price and quantity labels for all three equilibria
• The functions named: rationing along D, signal and incentive from the higher price and profit

A common mistake

The new supply is marked as a point further along S2. Replanting changes how much farmers can supply at every price, so it shifts the whole curve right, to S3. A movement along S2 would need the price to rise further, and the price falls.

Exam question

Using the market for cocoa as an example, explain how the price mechanism allocates resources, and evaluate whether it does so efficiently.

Model answer

The price mechanism is the process by which prices set in markets decide what is produced, how and for whom. It works through three functions: prices ration scarce goods to those willing to pay, signal to producers where resources are wanted, and, through profit, give them an incentive to respond.

In 2023 and 2024 disease and drought cut the West African cocoa harvest. On a diagram supply shifted left from S1 to S2, creating excess demand at the old price of about $4,000 a tonne, and the price rose to a new equilibrium above $12,000. That price rationed cocoa: along the demand curve, chocolate makers who valued it least shrank bars, cut cocoa content and switched to substitutes, so quantity demanded contracted. It also signalled scarcity and created large profits for anyone who could grow cocoa.

The profit was the incentive. Farmers in Ivory Coast and Ghana treated disease, pruned and replanted; producers in Ecuador, Nigeria and Brazil expanded. By 2026 the response arrived: Ghana’s harvest rose 26% in a year, supply shifted right to S3 and the price fell to about $3,000, below where it had started. Resources had been drawn into cocoa by the high price, and now losses at $3,000 will push the highest-cost producers back out. Across the economy the same process, repeated in every market, moves land, labour and capital towards what consumers are willing to pay for, without any central plan.

**However,** the mechanism is efficient only in a limited sense. Because cocoa trees take years to bear fruit, supply responds with a lag and the market overshoots from shortage to glut, a cobweb pattern that leaves smallholders who expanded at the top selling at the bottom; Ghana and Ivory Coast cut their guaranteed farm-gate prices sharply in 2026. Prices also weight the wealthy more heavily than the poor, ignore costs that fall on third parties such as deforestation, and cannot allocate goods that have no price. The price mechanism allocated cocoa faster than any planner could have, but at a cost in volatility and hardship that explains why governments intervene with buffer stocks, guaranteed prices and regulation.