Strictly it won't be. According to their press release, most of the time the Corporation will just refer to themselves as The City of London, which makes sense as practically no-one under 60 remembers/understands the wider use of Corporation in local Government pre-1974.
More cynically, when used in its wider business sense, "corporation" frequently gets preceded by "evil, monopolising..." - not helped by this recent film
Hehe - but The Corporation explains how the original benign meaing of the word has become polluted by the activities of modern companies. A good corporation could help to retrieve the original meaning, so maybe the City should continue with this name in the interests of rehabilitating the reputations of the evil corporations which presently control it?