Renditelitan
Chieftain
I have found no text stating that this is not supposed to be possible anywhere. The civic text states that foreign corporations have no effect on your civilization. But Founding a corporation while running Mercantalism is not possible as the option is grayed out.
I'm betting that this is a bug in the code for Mercantalism as is views the founding of the headquarters as the founding of a corporation (and since you don't have the HQ, you can't found it), instead of as the creation of a World Wonder. Thus preventing you from founding the HQs.
While minor, it can really screw up an economy. An whether to found a corporation or spend 2 turns in anarchy and 5 turns with abysmal trade shouldn't be an option that has to be considered.
I'm betting that this is a bug in the code for Mercantalism as is views the founding of the headquarters as the founding of a corporation (and since you don't have the HQ, you can't found it), instead of as the creation of a World Wonder. Thus preventing you from founding the HQs.
While minor, it can really screw up an economy. An whether to found a corporation or spend 2 turns in anarchy and 5 turns with abysmal trade shouldn't be an option that has to be considered.