I've been saying for a long time that the real definition of 'personhood' is the ability to take liability. If something can be sued in court (not counting civil forfeiture sophistry) then it counts as a person.
How about "If it gets sentenced to prison time" instead because corporations routinely get sued in court only to be charged a small percentage of the profit they make through criminal activity and that isn't "liability" it's just paying the justice system a cut of the action as a cost of doing business.