The $32 billion (28.8 billion euros) will be distributed via Alwaleed Philanthropies to charities promoting disease eradication, disaster relief and women's rights, the prince said.

But Alwaleed, nephew to the Saudi King Abdullah who died earlier this year, did not say in an initial statement what impact, if any, the gesture would have on his holdings. He also made clear that though there was a "well-devised plan" to give out the money, there was no deadline by when the donation would be spent.

His statement said that the "philanthropic pledge will help build bridges to foster cultural understanding, develop communities, empower women, enable youth, provide vital disaster relief and create a more tolerant and accepting world."

Alwaleed, who describes himself as a "global investor, leader, family man" on his website, said he would head a board of trustees tasked with spending the money, adding that his pledge would still be used after his death "for humanitarian projects and initiatives." The board is said to be modeled on the Bill and Melinda Gates Foundation.

At a press conference, he said his pledge was modelled on the Bill and Melinda Gates Foundation and other philanthropic funds in the United States.

"This is very much separate from my ownership in Kingdom Holding," Alwaleed told reporters on the 66th-floor headquarters of the publicly listed company which he chairs.

As well as media investments, Kingdom Holding has interests ranging from the Euro Disney theme park to Four Seasons hotels and Citigroup.

In the ultra-conservative Islamic kingdom, Alwaleed, who holds no government rank, is considered unusual, not least for his occasional comments about economic issues.

In 2013, Forbes magazine listed him as the world's 26th richest man, with a personal fortune of $20 billion, though he disputed the figure, claiming he had been undervalued by $9.6 billion. He is said to own nine private aircraft, including a Boeing 747.

bk/uhe (AFP, Reuters)