The economic entity principle states that the recorded activities of a business entity will be kept separate from the recorded activities of its owner(s) and any other business entities. This means that you must maintain separate accounting records and bank accounts for each entity, and not intermix with them the assets and liabilities of its owners or business partners. Also, you must associate every business transaction with an entity.
A business entity can take a variety of forms, such as a sole proprietorship, partnership, corporation, or government agency. The business entity that experiences the most trouble with the economic entity principle is the sole proprietorship, since the owner routinely mixes business transactions with his own personal transactions.
It is customary to consider a commonly-owned group of business entities to be a single entity for the purposes of creating consolidated financial statements for the group, so the principle could be considered to apply to the entire group as though it were a single unit.
The economic entity principle is a particular concern when businesses are just being started, for that is when the owners are most likely to commingle their funds with those of the business. A typical outcome is that a trained accountant must be brought in after a business begins to grow, in order to sort through earlier transactions and remove those that should be more appropriately linked to the owners.
The economic entity principle is also known as the business entity assumption, business entity principle, entity assumption, entity principle, and economic entity assumption.