Profit as rent of ability: one of the most widely known theories of profit was propounded by F.A. Walker. According to him profit is the rent of is the difference between the earnings of at least and the most fertile land. Profit is the difference between the formulating his profit theory, Walker and as the most efficient enterprises in formulating his profit theory each firm summed a state of perfect competition in which all firms are presumed to possess equal managerial ability. Each firm would receive only the wages of management which, in walker's view, forms no part of pure profit. He regarded wages of management as ordinary wages. Thus under perfectly competitive conditions, there would be no pure profit and all firms would earn only managerial wages, which is popularly known as "normal profit".