The reason being is that every company is a distinct entity or enjoys a separate legal existence from its shareholders and members. (instantassignmenthelp.com)
The Corporation is unique among British local authorities for its continuous legal existence over many centuries, and for having the power to alter its own constitution, which is done by an Act of Common Council. (en.wikipedia.org)
These informal local political parties often have no formal legal existence, exist in only one or two different local governments at any one time, tend to be focused on political issues particular to the locality, and tend to last for only one, or at most, just a few, election cycles. (politics.stackexchange.com)