DraftKings is making a $20 billion offer to acquire U.K. online sports betting company Entain, people familiar with the matter told CNBC’s David Faber on Tuesday.

The offer is largely in DraftKings stock, along with cash, according to the sources.

Entain shares jumped about 18% in London trading Tuesday. DraftKings shares closed 7.4% lower Tuesday after the news.

On Monday, before news of the deal, the enterprise value of Entain was about £13.2 billion, or $18 billion.

In a filing with the London Stock Exchange, Entain’s board confirmed that it received a proposal from DraftKings, which would include a combination of stock and cash. The filing did not contain any information on the price of the offer.