According to this study, 737 Trans-National Corporations (TNCs) control 80 per cent of the global economy. This includes a ‘super entity’ of 147 at the core that controls 40 per cent of the economic value of TNCs in the world. Here is an interesting theoretical framework to describe the phenomenon: Core periphery theory (Allen Sens).
Reference: Vitali, S., Glattfelder, J. B., & Battiston, S. (2011). The network of global corporate control. PLoS ONE, 6(10), pp. 1-36.