When some goods or productive factors are completely fixed in amount, regardless of price, the supply curve is

When goods or productive factors are completely fixed in amount regardless of price, the supply is considered perfectly inelastic. In this scenario, the quantity supplied remains constant at a specific level, and the price elasticity of supply (PES) is zero [1]. Graphically, this relationship is represented by a vertical supply curve [1]. A vertical curve indicates that the supply is completely insensitive to price changes; whether the price rises or falls, the quantity supplied does not change [1]. This often occurs in the short run when factors of production cannot be increased or for unique goods like land or rare art where the total stock is fixed. In contrast, a horizontal curve represents perfectly elastic supply, while upward-sloping curves represent varying degrees of price elasticity where quantity responds positively to price increases [1].

Sources

1. [1] Microeconomics (NCERT class XII 2025 ed.) > Chapter 4: The Theory of the Firm under Perfect Competition > 4.7 PRICE ELASTICITY OF SUPPLY > p. 66