Singapore’s oil companies last week raised retail prices for gasoline and diesel by 4 Singapore cents a litre. (US$1=S$1.7). Citing “global market conditions”, Caltex Singapore Pte Ltd said its three gasoline grades now sell for S$1.415, $1.498 and $1.59 a litre while its new diesel price is $0.852. ExxonMobil said its gasoline grades now cost…