Outside the rebellious South, the Union war mobilization probably fell most heavily upon the financial system, permanently changing both the internal organization of national capital markets and the relationship of the central state to finance capitalists. In part, the policies adopted by the Union were shaped by the North's reliance on uncontrolled markets for supplies and manpower. Voluntary transactions with private manufacturers and civilians required a sound currency and guarantees as to the future credit of the state. At the same time, the huge demands placed upon the domestic economy by the war mobilization forced the financial system off the gold standard – up to this point in American history, the maintenance of that standard had been the foundation upon which the state's credit had rested. As a result of the abandonment of the gold standard and a reliance on unregulated markets for supplies, the Union developed revenue policies that transformed a large part of the financial community into clients of the state. Financiers were both enticed and coerced into becoming the agents of Union fiscal policy and subsequently cooperated with the Treasury in marketing government debt securities and managing the circulation and value of Union currency.

When the Civil War ended, the interests of finance capitalists and the American state were probably more closely linked than at any other point in the nineteenth century.