By Nerijus Adomaitis and Lefteris Karagiannopoulos
OSLO (Reuters) - Norwegian-born shipping tycoon John Fredriksen, one of the world's richest men, has a succession plan ready but it depends on many things, such as his health, he told Reuters on Thursday.
Fredriksen, nicknamed "Big Wolf" or "Big John", is the top shareholder in rig firm Seadrill, oil tanker firm Frontline, fish farmer Marine Harvest and dry bulk carrier Golden Ocean, among other holdings.
Forbes magazine estimates his net worth at $9.9 billion.
"It has been planned. But it depends on many things," the billionaire investor, 73, said in an interview. "Like health. It may take 10 or 15 years. I have not made up my mind (on when)."
Fredriksen is trying to restructure the $14 billion debt and liabilities of Seadrill, once the world's most valuable rig firm but which was hard hit when oil firms cut investments in the wake of a 2014 crash in oil prices.
He has also been trying to take full control of tanker firm DHT Holdings.
On Thursday he declined to give details about the progress of the talks on Seadrill's debt or of his battle for DHT.
Fredriksen rose from humble origins to become the shipping world's leading magnate.
He began his career as a messenger boy at a shipping company in Oslo, later establishing himself on the shipping scene during the 1960s and 1970s in Singapore and New York.
He made his fortune in the "tanker wars" of the 1980s during the Iran-Iraq conflict, when his vessels risked missile fire to load and transport crude oil cargoes from the region.