IHS has signed a definitive agreement to acquire Polk and the acquisition is subject to customary closing conditions and puts to an end speculation that the 143-year-old family-owned business was to go public.

In March, Polk hired New York investment bankers Evercore Partners to examine options including selling the company, an initial public offering or even expansion through acquisitions.

At the time, Reuters reported that potential takeover bids could be as high as $1bn for the firm, which generated revenues of $359m in 2011.