What is the correct spelling of the plural possessive form of ‘business’?

The spelling business's is a possessive form (of, about, or owned by one business). The spelling of the plural of business is businesses, and the plural possessive is businesses'. Single possessive of business? Possessive of the singular business is business's; possessive of the plural businesses is businesses'.

The noun business can be countable or uncountable. In more general, commonly used, contexts, the plural form will also be business . However, in more specific contexts, the plural form can also be businesses e.g. in reference to various types of businesses or a collection of businesses .

Businesses is correct. It is the plural of Business. The apostrophe is used to show that something belongs to something else (It's called the Genitive case). Normally (though not always) the apostrophe or apostrophe + s are followed by a noun. e.g. The dog's bones = the bones that the dog has...one dog.

There are five basic rules for possessive nouns. Rule #1: Making singular nouns possessive. Add an apostrophe + "s" to most singular nouns and to plural nouns that don't end in "s.". You'll use this rule the most, so be sure to pay attention to it.