"company whose purpose" is correct and usable in written English.
It can be used whenever you want to talk about the purpose of a particular company. Example: The new startup is a tech company whose purpose is to revolutionize the way we communicate.
Users, but not customers, of a company whose purpose is undefined.
Welcome to Aviva — the company whose "purpose is to help people defy uncertainty".
The company whose purpose is survival is more like a river.
"Pemex has to become a competitive and integral company whose purpose is to maximize oil revenue, contribute to the nation's development and satisfy the needs of its clients".
Since nobody expected his co-founder David Filo to take up the reigns, Yahoo suddenly became a company whose purpose was merely to drive the share price up.
CASSANDRA is clearly (not necessarily the best word when it comes to his predictions…) not the only soothsayer in town witness the latest from Trendwatching.com, a company whose purpose is in its name.
"To rely on a bunch of good-hearted insurance companies whose purpose is, quite frankly, to make money — to expect them to go into the charitable business of taking care of a lot of hungry and impoverished kids — strikes me as the height of folly," Mr. Dingell said.
To break the deadlock, McKinsey proposes the formation of special companies whose purpose would be to destroy capacity and jump-start a restructuring process.
It was a party whose purpose was in question.
Chemical, and its subsidiary Texas Commerce Bank, will earn fees by handling the finances of a new company whose sole purpose is to make the lower-cost loans.
He had recently been stung by a 1 percent scandal of his own: setting up a company whose sole purpose was to donate $1 million to a political-action committee that supported Romney.
