From the article:

Jerome Levy began the derivation of the profits identity and his serious interest in economics in 1908; unemployment was high in that recession year and no unemployment insurance or other public safety-net was available to aid those who lost their jobs. To him, the profits equation would be a tool to help address the scourge of unemployment.

Michael Kalecki derived that identity about 30 years later, some years after he became deeply involved with economics (Kalecki 1969). He was disturbed by unemployment and poverty. Indeed, he believed that unemployment was a chronic feature of capitalism.

Jerome Levy, who was educated to be a physicist, was a small wholesaler of knit goods in 1908. Kalecki was an engineering student who abandoned his studies because of limited funds.

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Kalecki noted that capitalists' markup (their rate of profit on sales or revenue) determined the distribution of consumption between them and workers. He believed that capitalism tended to become increasingly monopolistic. Markups therefore tended to widen. He wrote, ". . .if the effect of the increase in the degree of monopoly upon the distribution of national income is not counteracted by other factors, there will be a relative shift from wages to profits . . ." (Kalecki 1969)

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Levy was not necessarily opposed to monopolies. If they operated at a satisfactorily low enough rate of profit, they might even be desirable. He sought means to prevent industries from securing excessive profits, profits that could not be justified by an industry's productive risk. He proposed taxing such profits away. If an industry's profits were excessive, the tax would be on the entire industry and, in effect, confiscate the excess. This scheme allowed an individual firm in a competitive industry to retain an above average return as a result of being more efficient and astute in designing, producing, and marketing its products than its competitors.

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Leading to an early recognition of inventory's role was Jerome Levy's 1917 application of his understanding of fiscal policy. On a number of occasions he said that civilian business was fearful of what would ensue when the United States entered World War I, but that looking into his equation he knew that he should buy all the merchandise that anyone would give him the credit to carry.

That move changed Levy's business from struggling to substantial. Willy Nagel, the sales representative of Utica Knitting Mills, Jerome Levy's principle supplier told me this story. In late 1919 and early 1920, the demand for his company's products exceeded supply and all its customers were placed on allotment. But since Jerome Levy had acquired special status, Nagel handed an order form to him and said, "Write down everything you want and I'll see that you get it." But his customer, aware of the speculation in inventory, handed the form back and said, "I'm not buying anything." This decision required not only a great deal of confidence but also courage because all the small retailers that were Levy's customers depended on his having an adequate inventory.

A few months later the United States was in a deep recession and the prices of knit goods fell about 35 percent. At the beginning of 1929, Levy, noting that the country was heading for serious trouble because it had more plant and equipment than it needed, began to liquidate his business.