Nexus d20 Cyberpunk

From the introduction:

Megacorps are the nations of Cyberpunk. Old fashioned nations are mostly Balkanized and/or puppets of the Megacorps. They poured money into elections and gained control over the local governments. Then they told everyone that the governments were too abusive of power and too large so they took them apart and deregulated. Now all the national Megacorps have gained extraterritoriality which means that they are in effect sovereign nations now. They have effectively diplomatic immunity from the police, the local governments, and no taxation on them.