Norwegian-born billionaire John Fredriksen lost the control of the company, once the world's largest driller by market cap, to its creditors over two debt restructurings since 2014.

Norwegian-born billionaire John Fredriksen lost the control of the company, once the world's largest driller by market cap, to its creditors over two debt restructurings since 2014.

The shale boom made the US the world’s top oil producer in recent years, ahead of Saudi Arabia and Russia. But with many of ...