Crude oil prices remain volatile, later on Tuesday they slipped back after earlier hitting a one-month high above 50 dollars a barrel. That spike was because of Israel’s incursion into Gaza and the dispute between Russia and Ukraine over natural gas; both events heightened investors’ concern about supply disruptions. European shares finished the session higher again on Tuesday.Investors are hoping that stimulus plans by US President-elect Barack Obama will boost the markets. In addition, top German officials said the Berlin government’s second fiscal stimulus could reach 50 billion euros. That is nearly double the amount expected just a week ago. Carmakers stocks rose after Porsche increased its stake in Volkswagen to more than 50 percent. In the mining sector, Rio Tinto and Xstrata enjoyed big gains as copper prices perked up.