Billionaire Prince Alwaleed bin Talal said the Gulf Arab kingdom needed to reduce its reliance on crude oil and diversify its revenues.
His warning comes as rising shale energy supplies in the United States cut global demand for Saudi oil.
In an open letter to his country’s oil minister Ali al Naimi and other government heads, published on Sunday via his Twitter account, Prince Alwaleed said demand for oil from Organisation of the Petroleum Exporting Countries (Opec) member states was “in continuous decline”.