Even as Rockefeller and Carnegie built their empires, the era of the “robber barons,” as they were dubbed by their detractors, was drawing to a close. Increasingly, businesses replaced partnerships and sole proprietorships with the anonymous corporate structure that would come to dominate the twentieth century. At the same time, mergers led to the creation of huge new corporations.

Banks and financiers played key roles in this consolidation, so much so that the decades at the turn of the twentieth century can be characterized as a period of finance capitalism—investment sponsored by banks and bankers. When the depression that followed the panic of 1893 bankrupted many businesses, bankers stepped in to bring order and to reorganize major industries. During these years, a new social philosophy developed that helped to justify consolidation and to inhibit state or federal regulation of business. A conservative Supreme Court further frustrated attempts to control business by consistently declaring unconstitutional legislation designed to regulate railroads or to outlaw trusts and monopolies.