Iranian companies are trying to buy a Swiss petroleum refinery, according to people familiar with the deal, as Tehran seeks outlets for oil that may return if western sanctions are lifted later this year. Petro Farhang, the oil-investment subsidiary of Iran’s teacher pension fund, and Ghadir Investment, a conglomerate with petrochemical businesses which is controlled by Iranian pension funds, have registered a formal expression of interest to buy a refinery in Collombey, Switzerland, controlled by Libyan firm Tamoil Suisse, according to people familiar with the move. Stephane Trachsler, general secretary of Tamoil Suisse, said the company had rejected all potential bidders so far. He declined to confirm the approach by the Iranian companies but he said one potential bidder had been refused […]