When making the word business possessive do you need to add an apostrophe AND an s or just an apostrophe?

The technically correct spelling is business's. Some users are not required to conform to specific styles and will use the apostrophe only form.

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"It is technically correct (but slightly out of date) to use "business's" but the appearance of the Word seems a little awkward. For that reason, "business' " has become acceptable to most people."

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If you are discussing a single business, you may show possession or ownership by either using an apostrophe alone, as in "the business' new location" or an apostrophe with an "s", as in "the business's new location." However, the business's new location is more common only because of the way the Word is actually pronounced.

The general rule is that a single syllable Word always uses an apostrophe followed by an "s" to show possession, but if the Word is two or more syllables, you may drop the "s" and just use the apostrophe. However, if the single Word ends in an "s" as "business" does, then "business's new location" is more commonly used. However, both are grammatically correct.

(However, if you wish to show possession for several businesses, go with "the businesses' location" and drop the extra "s".)