How to add possessives in AP Style

Adding possessives to your writing can be confusing. When do you add an apostrophe with or without an “s”? Names can be particularly tricky—especially those that end with “s” or “z.” Here are the basics in AP Style:

For plural nouns not ending in s: Add ‘s.
Example: Women’s rights, teacher’s handbook, researcher’s lab

For plural nouns ending in s: Use only an apostrophe.
Example: the dogs’ leashes, the students’ schedules

For singular common nouns not ending in s: Add ‘s.
Example: the alumni’s email, the student’s folder

For singular common nouns ending in s: Add ‘s.
Example: the witness’s statement, the waitress’s notepad

For singular proper names ending in s: Use only an apostrophe.
Example: Achilles’ heel, Harris’ campaign, Hercules’ labors

For singular proper names ending in z: Add ‘s.
Example: Mrs. Sanchez’s children, Walz’s speech

For plural proper names ending in s, z or ch: Add es’s.
Example: the Joneses’s house, the Gonzalezes’s party

If you have questions about AP Style in your writing, U of M students, faculty and staff have access to the AP Stylebook via U of M Libraries (note Stylebook access is limited to 25 simultaneous users). You can also reach out to the University Relations PR team at unews@umn.edu.