Zon Multimedia SGPS SA (ZON) rose as much as 1.3 percent after shareholder Isabel dos Santos increased her stake in Portugal’s biggest cable-television provider to 14.9 percent.

Zon rose as much as 3 euro cents at 8:07 a.m. in Lisbon. The gain was the biggest in Portugal’s benchmark PSI-20 Index, which rose 0.1 percent.

Dos Santos agreed to buy 4.9 percent of the Zon through her Amsterdam-based holding company Jadeium, adding to the 10 percent stake she already controlled through Kento Holding Ltd., Lisbon-based Zon said in a regulatory filing yesterday.

Isabel dos Santos, the daughter of Angolan President Jose Eduardo dos Santos, is now Zon’s biggest shareholder, according to data compiled by Bloomberg.

To contact the reporter on this story: Henrique Almeida in Lisbon at halmeida5@bloomberg.net

To contact the editor responsible for this story: Jerrold Colten at jcolten@bloomberg.net