The announcement is the latest step in Exor's investment campaign, propelled two years ago by the $9 billion it raised from the sale of its reinsurer PartnerRe to France's Covea. It is using the cash for M&A and share buybacks.

"Exor becomes a long-term investor in Clarivate, endorsing the strategic direction set out by the company's management and board," the companies said.

(Reporting by Giulio Piovaccari, editing by Gavin Jones)