1318 GMT - Copper prices retreat as a firmer U.S. dollar and expectations of further interest-rate hikes weigh on sentiment across the metals complex. Three-month copper futures on the LME are down 0.6% to $14,693 a metric ton. The dollar index--which measures the greenback against a basket of other currencies--rises 0.2% to 100.83, making dollar-denominated commodities more expensive for overseas buyers. According to the CME's FedWatch tool, traders currently price in a 55% probability that the Federal Reserve will hike interest rates next month. Higher rates typically strengthen the U.S. dollar and increase the cost of holding raw materials, hurting copper.