The possessive case denotes ownership or possession of one thing by another (41a).

Forming possessives of singular nouns and indefinite pronouns

Add an apostrophe and -s to form the possessive of most singular nouns, including those that end in -s, and of indefinite pronouns (40e).

The bus’s fumes overpowered her.

Star Wars made George Lucas’s fortune.

Anyone’s guess is as good as mine.

Apostrophes are never used with the possessive forms of personal pronouns: yours, his, hers, its, ours, theirs.

Forming possessives of plural nouns

For plural nouns that do not end in -s, add an apostrophe and -s.

For plural nouns ending in -s, add only the apostrophe.

Forming possessives of compound words

For compound words, make the last word in the group possessive.

The secretary of state’s speech was televised.

My in-laws’ disapproval dampened our enthusiasm.

Showing possession by more than one owner

To signal individual possession by two or more owners, make each noun possessive.

The differences between Ridley Scott’s and Jerry Bruckheimer’s films are enormous.

Scott and Bruckheimer make different films.

To signal joint possession, make only the last noun possessive.

Wallace and Gromit’s creator is Nick Park.

Wallace and Gromit have the same creator.