Check-the-box

For United States income tax purposes, a business entity may elect to be treated either as a corporation or as other than a corporation. This entity classification election is made by filing Internal Revenue Service Form 8832. Absent filing the form, a default classification applies. U.S. corporations of the type that can be publicly traded must be treated as corporations. There is a list of specific foreign entities that must be treated as corporations. The election is effective for Federal and most state income tax purposes.

If an entity is not classified as a corporation, it is treated as a partnership for U.S. tax purposes if it has more than one owner, or is a disregarded entity if it has a single owner (i.e. is treated as part of the single owner).

The classification of either a U.S. or non-U.S. entity for U.S. tax purposes has no effect for purposes other than U.S. income tax.

An entity, which is eligible to make an election, is referred to as an eligible entity. Generally, a corporation organized under U.S. federal or state statute (and referred to as a corporation, body corporate or body politic by that statute) is not an eligible entity. However, the following types of business entity are treated as eligible entities:

The list of foreign entities classified as corporations for federal tax purposes (so called per se corporations, not eligible to make an entity classification election) includes, as of September 2009:

In 2013, the IRS added a Croatian dionicko drustvo to the list of per se corporations.

An eligible entity is classified for federal tax purposes under the default rules described below unless it files Form 8832 or Form 2553, Election by a Small Business Corporation, to elect a classification or change its current classification. The IRS uses the information entered on the form to establish the entity's filing and reporting requirements for federal tax purposes. Certain domestic and foreign entities that were in existence before January 1, 1997, and have an established federal tax classification generally do not need to make an election to continue that classification. If an existing entity decides to change its classification, it may do so subject to the 60-month limitation rule.

Unless an election is made on Form 8832, a domestic eligible entity will be classified by default as:

Unless an election is made on Form 8832, a foreign eligible entity will be classified by default as:

...
Wikipedia