There are two accepted forms for possessive singular nouns ending in s:
Add an apostrophe (') after the existing s at the end of the word: business'
Add an apostrophe s ('s) after the existing s at the end of the word: business's
Examples:
My business' increase is due to advertising.
My business's increase is due to advertising.
The plural of business is businesses.
Not transposed. The correct spelling is business.
businesses is the plural form.
The plural of activity is activities.
languages
geese
Halos is the correct way to spell the plural form.
The plural of ostrich is ostriches.
entree entrée is actually the correct way to spell it.
That is the correct (capitalized) spelling of the plural noun "Martians."
The correct spelling of the noun is privilege, plural privileges.
The plural way to spell studio is studios.
Absences is the correct spelling.
That is the correct spelling of the plural noun "mushrooms."
Businesses' when making a plural noun into a possessive just add an apostrophe ( ' )not apostrophe s ( 's ) The girl's toys. The girls' teacher