Prince Alwaleed Bin Talal Al-Saud, the world’s 15th-richest person, sold his Airbus A380 jet plane in the past four months, according to Shadi Sanbar, chief financial officer of the billionaire’s Kingdom Holdings Co.

The 57-year-old, who bought the plane in 2007, used the proceeds from the sale to expand his investments in Saudi Arabia and the greater Middle East, Sanbar said in an email. He would not disclose the buyer or the sale price, citing confidentiality agreements.

Alwaleed “has been talking about investing in real growth companies, with genuine employment opportunities,” said Saud Masud, chief executive officer of New York-based investment firm SM Advisory Group in a phone interview Friday. “He needs cash for that type of growth.”

The chairman of Riyadh-based Kingdom Holding has a net worth of $29 billion, according to the Bloomberg Billionaires Index. He bought the plane, which is manufactured by Toulouse, France-based Airbus SAS, in 2007. The list price of an A380 was $319 million at the time. He never took possession of the plane.

Alwaleed’s fortune has surged $8.5 billion since April 2012 as Kingdom shares have almost doubled in value. The diversified investment company, which controls stakes in Citigroup Inc. and News Corp., accounts for more than two-thirds of Alwaleed’s net worth, according to the Bloomberg ranking.

Airbus announced Alwaleed’s purchase at the 2007 Dubai Air Show. The billionaire allowed the company to name him as the first private jet customer of an A380, which is 239-feet long and can seat as many as 853 passengers when used for commercial flights, according to Airbus’ website.

David Velupillai, a spokesman for Airbus Corporate Jets in Blagnac, France, said the company had not released any more details about Alwaleed’s purchase, and confirmed that the building of the jet was complete, with the exception of its cabin.

Most corporate-jet buyers customize the cabin interior to their taste, according to Howard Guy, chief operating officer of Design Q, a Redditch, U.K.-based design consultancy that focuses on the luxury transport sector. Design Q made an unsuccessful bid to customize Alwaleed’s jet in 2009.

“We worked on it for about six months,” Guy said by phone Thursday. “We basically came up with the layouts for the aircraft. Our designs were based on how we interpreted what he was looking for. It was a whole blend of styles.”

Guy’s designs, which were published by London’s the Daily Mail newspaper in December, included a concert hall and a marble steam room.

Alwaleed has built much of his fortune investing in companies such as Apple Inc. and News Corp. In the past several years, the billionaire said he has been reallocating his portfolio in favor of the Middle East. He has more than $1.3 billion invested in public and private equities in the region, according to Sanbar.