A purely competitive firm that is earning positive profits in its short-run equilibrium situation will continue to earn positive profits at the long-run equilibrium.

Short-Run Equilibrium

A condition in a market or economy where all forces are balanced, but only temporarily; prices and output may change until a long-run equilibrium is achieved.

Long-Run Equilibrium

A condition where an economy or market achieves a stable state after adjustments, where supply equals demand over an extended period.