REA Group, the property listings company majority owned by News Corp, is considering buying Rightmove to create a global real estate company, the Australian firm said on Monday, sending the British housing portal’s shares soaring.

Shares in London-listed Rightmove surged as much as 25.4% to their all-time high of 6.97 pounds, and the stock was the top percentage gainer on the FTSE 100 index. The company declined to comment.

Britain’s largest property portal Rightmove had a market value of 4.36 billion pounds ($5.73 billion) as of Friday’s close. It makes money from listing real estate agents on its website.

Analysts at Investec in a note agreed with REA that the offer and the enlarged group presents a highly attractive investment opportunity, given an easing interest rate environment in the U.K. and recent new investment starting to pay off.