The possessive of proper nouns like "Perez" - with or without an "s"?

Question

A reader named Sonny, in the U.S., asked how to write the possessive form of a proper noun (the name of something or someone) ending in an s or z sound, such as Perez or Burns.

Answer

There is a lot of disagreement about the answer to this question. To form the possessive of a proper noun ending in an s or z sound, some people use apostrophe + s, as in Perez’s and Burns's, and others prefer an apostrophe alone, as in Perez’ and Burns's.

The best advice I can give you is that if you are writing for a class, or if you work for a company or other institution, find out which style your teacher or manager prefers and use it. Otherwise, decide which style you like best and use it. However, be consistent – don’t use both styles in the same report, letter, memo, essay, or whatever you are writing.

One more thing: Since my name ends in –s (Mairs), I think about this question a lot. For a long time I thought there was only one correct answer, but I have since learned that that's not true.

I hope this helps.