The Monthly Review article points to similar concentration of market power and emergence of monopolies across different industries. The number and percentage of US manufacturing industries that have a four-firm concentration ratio of 50 percent or more have risen dramatically since the 1980s. More and more industries in the manufacturing sector of the economy are tight oligopolistic or quasi-monopolistic markets characterized by a substantial degree of monopoly.
This concentration of market power has been a constant theme across sectors. The graphic below shows the rise in four-firm concentration ratios in six key retail sectors and industries, over the fifteen-year period, 1992-2007. Most remarkable was the rise in concentration in general merchandise stores (symbolized by Wal-Mart), which rose from a four-firm concentration ratio of 47.3 in 1992 to 73.2 percent in 2007; and computer and software stores from a four-firm concentration ratio of 26.2 percent in 1992 to 73.1 percent in 2007.
Another graphic highlights the rising share of the top 200 US corporations as a percentage of total business revenues in the US economy over the 1950-2008 period. The revenue of the top two hundred corporations has risen steeply since the mid-nineties.
In this context, a pathbreaking scientific study of the network of global corporate control by Stefania Vitali, James B. Glattfelder, and Stefano Battiston has thrown up several astounding insights. They mined the Orbis 2007 database of 37 million companies and investors worldwide and mapped the ownership and control networks of all the 43060 trans-national corporations (TNCs). Then they constructed a model of which companies controlled others through shareholding networks, coupled with each company's operating revenues, to map the structure of economic power. They write,
"We find that, despite its small size, the core holds collectively a large fraction of the total network control. In detail, nearly 4/10 of the control over the economic value of TNCs in the world is held, via a complicated web of ownership relations, by a group of 147 TNCs in the core, which has almost full control over itself. The top holders within the core can thus be thought of as an economic "super-entity" in the global network of corporations. A relevant additional fact at this point is that 3/4 of the core are financial intermediaries."