After the fall of Earth, the survivors found themselves scattered and without leadership. The governments had all but collapsed and what remained was weakened and ultimately powerless.
As a result, the people found themselves looking to their saviors, the corporations, for guidance. Most were living on ships or colonies owned by the corporations during this time, and simply had no other authority to turn to.
This era of desperation and confusion eventually led to the formation of a new government. The corporations began to band together to form larger, more effective, ruling bodies. And the largest of the corporate micro-governments, six in total, came together to charter a new nation that would encompass the whole of humanity. The corporations came to be called the Houses, and together they became the Coalition of Free States.
Every registered Coalition citizen is a member of a House, which fills the role of both local government and employer. The Houses enforce both the laws of the Coalition, and a set of House Laws that vary from House to House.
The House structure and govern themselves in different ways. Some are more business-like, while others take a more feudal approach. And unlike the nations of old, the Houses do not recognize borders. Regardless of where you are, you are expected to obey the laws of the Coalition and your House.
As corporations, the Houses operate all business in the Coalition. And while each House has different markets they specialize in, citizens can file to establish subsidiary companies that can produce or provide any sort of legal product or service. It is because of these subsidiaries that every House has ended up with at least some small stake in pretty much every market.