Whose vs. Who’s

The difference between the use of whose and who’s is similar to that between the use of its and it’s (discussed here).

whose – the possessive form of whom.

“The director, whose shares were recently acquired by the company, resigned last week.”

who’s – a contraction of who is. When you see the apostrophe, think “who is”.

“The plaintiff, who’s suing the defendant, is represented by a very competent counsel.”