6. A firm is profitable if total revenue exceeds total cost or, equivalently, if the market price exceeds its break -even price—minimum average total cost. If market price exceeds the break -even price, the firm is profitable; if it is less, the firm is unprofitable; if it is equal, the firm breaks even. When profitable, the firm’s per -unit profit is P − ATC; when unprofitable, its per -unit loss is ATC − P.