(Bloomberg) ? Frontline Ltd., the world?s second-biggest oil tanker company, said Oscar Spieler quit as chief executive officer because he wants a ?less stressing way of life?. He?s being replaced by Bjoern Sjaastad.

Spieler?s decision follows the loss of former chief financial officer Tom Jebsen, who quit in March for Norwegian oil rig operator Songa Offshore ASA. Spieler will remain at Frontline with responsibility for new businesses including vessels that transport oil rigs, the Bermuda-based company said last week.

Sjaastad, former CEO of chemical tanker company Odfjell ASA, served a prison sentence in Florida in 2004 for his part in price fixing of tanker shipments. Sjaastad was also fined $250,000 for the price fixing.