How To Write Posessiive Names Ending In S. The possessive of a plural name is always formed by adding an apostrophe after the final s ( the smiths’ dog, the harrises’ family home ). When it comes to grammar rules for apostrophe after s, you should be consistent in writing.

You need to use the best formula and stay consistent all the time. The two are pronounced exactly the same. Form the possessive of a plural.