Oslo

BILLIONAIRE John Fredriksen and his former top adviser Tor Olav Troim may not see eye to eye anymore, but they agree on this: It's time to buy offshore rigs again.

Foreseeing a boom in oil drilling a decade ago, the shipping tycoon and his right-hand man built one of the biggest offshore-rig companies before they fell out in 2014. With the industry now in the doldrums with assets at bargain prices, the two are at it again, this time as competitors.