Possessive pronouns show ownership, possession, or relationship like nouns.

Mine, ours, yours, hers, his, its and theirs are possessive pronouns.

This ribbon is surely yours. I gave away mine.

Hers is the fluffy puppy; his is the brown one.

My opinion about bullying could be different than yours.

NOTE: Unlike possessive nouns, possessive pronouns do not need an apostrophe –s as they already show ownership.

Incorrect: This book is her's.

Correct: This book is hers.

Incorrect: A friend of your's rang up.

Correct: A friend of yours rang up.