Monopsonie et marchés contestables
Introduit| English | Sens |
|---|---|
| monopsony/ˈmɒnəʊpsəni/ | monopsonie |
| sunk cost/sʌŋk kɒst/ | coût irrécupérable |
A decision you can investigate
- A supermarket chain is the only buyer of a region’s farm produce and the main local employer.
- Should it push the price it pays farms as low as possible?
Build the explanation
- A monopsony 买方垄断 is a market with a single buyer; monopsony power means one buyer can influence the price it pays. As an employer it faces the labour supply curve as its average cost of labour, so the marginal cost of labour lies above supply: attracting one more worker means paying more to all.
- It hires where marginal revenue product equals marginal cost of labour, then pays the wage on the supply curve, so employment and the wage are both below the competitive outcome. A contestable market has easy entry and exit with low sunk costs, so potential entrants discipline incumbents; limit pricing holds price below the short-run profit maximum to make entry unprofitable, unlike predatory pricing which prices below average variable cost to drive existing rivals out.
Work through the evidence
- With labour supply W = 2 + 0.05L and MRP W = 12 − 0.05L, a competitive market sets 2 + 0.05L = 12 − 0.05L, so 0.10L = 10: L = 100 workers at W = 7 per hour.
- The monopsonist’s marginal cost of labour is W = 2 + 0.10L; setting MRP equal to it gives 0.15L = 10, so L ≈ 67 workers, and the wage read off supply is W ≈ 2 + 0.05 × 66.7 ≈ 5.3 per hour.
Avec l'offre W = 2 + 0.05L et la MRP W = 12 − 0.05L, quel est le salaire dans un marché du travail concurrentiel ?
Difficulté 1/5 · 100 pièces + un petit bonus lors de la première réussite aujourd'hui
Offre = MRP donne 0.10L = 10, donc L = 100 et W = 7 ; le couple 67/5.3 correspond au résultat monopsonique.
Test the limits
- Monopsony gains for the buyer become consumer gains only if cost savings are passed on; suppliers may instead be squeezed into lower quality. Suppliers can organise into cooperatives and workers into unions to counter bargaining power.
- Contestability is a spectrum: high sunk costs make hit-and-run entry too risky, so even a concentrated market stays safe for incumbents; low sunk costs make even a monopoly behave competitively.
D'où provient le salaire du monopsoniste ?
Difficulté 1/5 · 100 pièces + un petit bonus lors de la première réussite aujourd'hui
MRP = MCL détermine l'emploi ; le salaire se lit ensuite sur la courbe d'offre inférieure.
Un acheteur unique nuit toujours aux consommateurs.
Difficulté 1/5 · 100 pièces + un petit bonus lors de la première réussite aujourd'hui
Le pouvoir de l'acheteur ne constitue une perte pour les consommateurs que si les économies de coût ne sont pas répercutées ; la contestabilité repose sur les conditions d'entrée, non sur le nombre d'entreprises.
Apply and explain your answer
- Does the monopsonist pay the wage where MRP equals the marginal cost of labour?
- No: that intersection fixes employment at about 67; the wage is read off the supply curve at that employment, about 5.3.
Qu'est-ce qui rend l'entrée « frappez et partez » crédible dans un marché contestable ?
Difficulté 1/5 · 100 pièces + un petit bonus lors de la première réussite aujourd'hui
De faibles coûts fixes irrécupérables permettent à un entrant d'entrer, de réaliser des profits et de sortir avec une perte minimale.
Use the terms precisely
- monopsony: A market with a single buyer, or one buyer dominant enough to set the price it pays.
- sunk cost 沉没成本: Spending that cannot be recovered on exit, such as industry-specific equipment.
Reliez les termes à leurs définitions.
Difficulté 2/5 · 140 pièces + un petit bonus lors de la première réussite aujourd'hui
Utilisez chaque terme selon la relation économique indiquée.
With labour supply W = 2 + 0.05L and MRP W = 12 − 0.05L, a competitive market sets 2 + 0.05L = 12 − 0.05L, so 0.10L = 10: L = 100 workers at W = 7 per hour. The monopsonist’s marginal cost of labour is W = 2 + 0.10L; setting MRP equal to it gives 0.15L = 10, so L ≈ 67 workers, and the wage read off supply is W ≈ 2 + 0.05 × 66.7 ≈ 5.3 per hour.
Monopsony gains for the buyer become consumer gains only if cost savings are passed on; suppliers may instead be squeezed into lower quality. Suppliers can organise into cooperatives and workers into unions to counter bargaining power. Contestability is a spectrum: high sunk costs make hit-and-run entry too risky, so even a concentrated market stays safe for incumbents; low sunk costs make even a monopoly behave competitively.
A monopsony is a market with a single buyer; monopsony power means one buyer can influence the price it pays. As an employer it faces the labour supply curve as its average cost of labour, so the marginal cost of labour lies above supply: attracting one more worker means paying more to all.