Operating as

A trade name, trading name, or business name is a pseudonym used by companies to perform their business under a name that differs from the registered, legal name of the business. Trade names are typically used by companies to conduct their operations under a simpler brand as opposed to using their formal name within all public communications, or when a desired name was not able to be registered by the business operator, or if that business is owned by a separate company, franchisee, or a sole proprietorship. Trade names are also used in drug nomenclature with specific policies and guidelines for use in academic publications (for example, atorvastatin (trade name Lipitor by Pfizer)).

The distinction between a registered legal name and a "fictitious" business name or trade name is important, as businesses with the latter give no obvious indication of the true identity of the entity that is legally responsible for their operation. Fictitious business names do not create legal entities in and of themselves; they are merely names assumed by existing persons or entities. Legal agreements such as contracts are normally made under the registered legal name of the business or owner, and the legal name must be used whenever a business sues or is being sued.

In the United Kingdom, Ireland, South Africa, Australia, New Zealand, Hong Kong and Zimbabwe (as well as some parts of the United States), the phrase trading as (abbreviated t/a) is used to designate trade names. In the United States and less often in Canada, the phrase "doing business as" (abbreviated DBA, dba, d.b.a. or d/b/a) is used. More common terms in Canada are operating as (abbreviated to o/a) and trading as (abbreviated to T/A). In English writing, trade names are generally treated as proper nouns.

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