長期競争均衡 II

Long-run competitive equilibrium requires three conditions: firms produce at their lowest average total cost, indicating efficient operations; firms earn zero economic profit, meaning no incentive to enter or exit the market; and market price adjusts so quantity supplied equals quantity demanded. This alignment ensures resources are allocated efficiently and societal welfare is maximized.

All firms have equal access to the same resources and technology, creating identical production cost curves. Since no firm can expect to earn economic profit by entering, and existing firms earn zero economic profit without losses, neither entry nor exit is motivated. This uniform cost structure ensures market stability.

The market price adjusts to a point where quantity supplied by the market exactly meets quantity demanded by consumers. This equilibrium eliminates shortages and surpluses while ensuring all production occurs at the lowest average total cost. The result is efficient resource allocation benefiting both firms and consumers.

Producing at the lowest average total cost means firms operate at maximum efficiency for their production level. Equal access to resources and technology allows all firms to function optimally on identical cost curves. This efficiency condition ensures firms minimize per-unit production costs while covering all expenses, including opportunity costs of capital and labor.

Societal welfare is maximized when resources are allocated most effectively, with supply perfectly aligned to consumer demand. Firms operate efficiently at minimum cost, consumers access goods at the lowest possible price, and no shortages or surpluses occur. This perfect alignment between production and consumption benefits the entire economy.

Firms earn normal profit, meaning they cover all costs including opportunity costs of capital and labor, but earn no additional economic profit. This zero economic profit condition reflects that firms recover their full economic costs without surplus returns. Normal profit ensures firms remain viable while preventing excess profitability that would attract new competitors.

Equal access ensures all firms operate under identical production cost curves, preventing any firm from gaining competitive advantage. This uniformity eliminates incentives for entry or exit and enables all firms to achieve the same minimum average total cost. Without equal access, some firms would earn economic profits, attracting entrants and disrupting equilibrium.