Shutdown is a short-run comparison with variable cost

The firm cannot avoid fixed cost by producing zero now.

If P≥ AVC, operating revenue covers variable cost and contributes something toward fixed cost, so producing at MR=MC loses less than shutdown. If P<AVC, revenue does not cover variable cost, so shutdown minimizes the loss at fixed cost. At P=min AVC, the firm is indifferent at the shutdown point.

Compare totals to see why. If production gives revenue of $1,000 and variable cost of $800, operation contributes $200 toward fixed cost. With fixed cost of $500, the operating loss is $300. Shutdown loses the entire $500. If variable cost were $1,100, operating would add $100 to the unavoidable fixed loss, so shutdown is better.

The average rule is the per-unit version. At the chosen output, P≥ AVC means PQ≥ AVC× Q=VC. Revenue covers variable cost. It need not cover ATC. A firm can operate with AVC<P<ATC and incur a smaller loss than shutdown.

Exit is a long-run decision. All costs are avoidable, so a firm leaves if revenue cannot cover total economic cost. This distinction matters: a firm can rationally operate at a short-run loss and later exit if conditions persist.

Shutdown means temporary zero production while fixed cost remains. Exit means releasing all avoidable inputs and leaving the industry. A seasonal firm may shut down during low demand and reopen. A persistently unprofitable firm exits when leases and commitments can end.

Operate now, exit later

At its best output, a firm has price $9, AVC $7, and ATC $12. It loses $3 per unit but covers variable cost and $2 per unit of fixed cost, so it operates now. If expected long-run price remains below minimum ATC, it exits when all inputs become avoidable.

Apply the shutdown rule after finding the best positive output. A fixed-cost increase changes neither MC nor AVC and therefore does not change short-run output or shutdown. A variable-cost increase can change both.

Shutdown is not bankruptcy or permanent closure. It is a current output choice of zero while fixed commitments remain. A firm can reopen when price again covers AVC. At P=min AVC, operation and shutdown both lose fixed cost. Above it operation contributes toward fixed cost, and below it operation adds to the loss.

A payment covering fixed cost can keep the firm solvent without changing its short-run output when MR and MC are unchanged. A per-unit subsidy changes effective MC and can expand output. This contrast tests whether the student understands the marginal reason behind shutdown rather than memorizing the word “loss.”

Apply the rule at the profit-maximizing positive output, not an arbitrary row. First find MR=MC, then read AVC there. A low AVC at an output the firm would never choose does not justify operation. If every feasible positive output has price below AVC, current output should be zero.