Firms as Market-Free Zones
"There is one last bastion of economic activity that proved remarkably resistant to the triumph of the market: firms, companies and, later, corporations. Think about it: market-societies, or capitalism, are synonymous with firms, companies, corporations. And yet, quite paradoxically, firms can be thought of as market-free zones. Within their realm, firms (like societies) allocate scarce resources (between different productive activities and processes). Nevertheless they do so by means of some non-price, more often than not hierarchical, mechanism!
The firm, in this view, operates outside the market; as an island within the market archipelago. Effectively, firms can be seen as oases of planning and command within the vast expanse of the market. In another sense, they are the last remaining vestiges of pre-capitalist organisation within… capitalism." (http://blogs.valvesoftware.com/economics/why-valve-or-what-do-we-need-corporations-for-and-how-does-valves-management-structure-fit-into-todays-corporate-world/)