supply

Supply in economics refers to the quantity of a good or service that producers are willing and able to offer for sale at various prices over a specific period, all else equal. The law of supply states that, ceteris paribus, higher prices induce greater quantities to be supplied. The supply curve is typically upward-sloping, reflecting higher marginal profitability at higher prices. Producers' willingness to supply also depends on costs, technology, and expectations about future conditions.

Determinants of supply include input costs, production technology, prices of related outputs, expectations of future prices, the number of sellers, and government policies such as taxes or subsidies. A non-price factor that changes these conditions shifts the entire supply curve. By contrast, a change in the price of the good causes movement along the curve, altering the quantity supplied without changing the curve's position.

Elasticity of supply measures responsiveness of quantity supplied to price changes. Elastic supply means producers can adjust output quickly as prices rise; inelastic supply indicates slower adjustment. Short-run supply is often more inelastic than long-run supply because some inputs or capacities cannot be changed immediately.

In a competitive market, supply interacts with demand to determine the equilibrium price and quantity. If quantity supplied exceeds demand at the prevailing price, a surplus results; if demand exceeds supply, a shortage occurs. Government interventions such as price floors, ceilings, taxes, and subsidies can alter these outcomes by changing incentives for production and consumption.

Outside economics, supply can refer to inventories or stock levels in logistics and business operations, such as the supply of medical equipment or energy resources, illustrating how the term is used to denote availability within a system.