Taken straight from the development thread:

[dev1034] Introduction of public companies

* [dev1034] Introduction of public companies

o Introduction of public company leaders in each city-state
o Introduction of public companies in Limsa Lominsa, Ul'dah, and Gridania to combat the threat to Eorzea

http://forum.square-enix.com/ffxiv/threads/294-dev1034-Introduction-of-public-companies


Doesn't look it's worth speculating about player driven companies.