I need an abstraction for the above terms.
In financial services, counterparty is often used.
Another hypernym could be account (although this sounds more like a bank account, or user/login account).
Also third-party account (although I've never heard of this one).
Which would be the correct way and/or most descriptive term?
My reason for asking is that I am designing a new database schema and want a base name from which these three types will inherit.
All of these people "transact" in business, and that's what they have in common.
Best Answer
As a professional economist, the term I would use to describe all those parties is (economic) agent. A broader, more generic term, is "trader."