When the profits of trade happen to be greater than ordinary, over-trading becomes a general error both among great and small dealers.
Adam SmithA monopoly granted either to an individual or to a trading company has the same effect as a secret in trade or manufactures. The monopolists, by keeping the market constantly understocked, by never fully supplying the effectual demand, sell their commodities much above the natural price, and raise their emoluments, whether they consist in wages or profit, greatly above their natural rate.
Adam SmithWhatever work he does, beyond what is sufficient to purchase his own maintenance, can be squeezed out of him by violence only, and not by any interest of his own.
Adam Smith