By Judy Vorfeld
Unfortunately, not all possessives use apostrophes. This includes the personal pronouns “its,” “theirs,” and “yours.” Since they are the most frequently misunderstood, let’s tackle them.
The wonderful but misunderstood apostrophe produces one of the biggest problems facing writers, as is evidenced on many Web sites and in all types of business documents. Let’s see if I can help.
Its or It’s?
The possessive form of the pronoun “it” is never written with an apostrophe, e.g., “Its start date is …” “What is its production record?” “Look at its nose!”
You only use an apostrophe when combining “it is” and “it has,” e.g., “It’s (it is) delicious,” or “It’s (it has) been wonderful.”
The children insisted the idea was theirs (not theirs’). Theirs isn’t abused that often, but it’s something to remember.
Your or You’re?
Your is a possessive form of the personal pronoun, e.g., “I like your Web site…” or “Thanks for giving so much money to this project.” Both in the same sentence: “Your knowledge of your product shows that you’re a dedicated salesperson.”
You’re is a contraction of the words “you” and “are,” e.g., “You’re up for an award. Someone said you’re leaving.”
Bottom line: No apostrophe for these possessive pronouns:
Its His Ours Theirs
Whose Hers Yours
Test yourself: write a sentence like, “I want to investigate its potential.” If you’re tempted to use an apostrophe, write it out as a contraction, and see if it makes sense, e.g., “I want to investigate it is potential.” Works every time.
More help at:
Chicago Manual of Style, 15th Edition (University of Chicago Press).
A Writer’s Reference, Fourth Edition (Hacker).