New York, NY -- (SBWIRE) -- 01/08/2013 -- Signet Jewelers Ltd. (NYSE: SIG), a specialty retail jeweler in the U.S. and U.K., is up sharply in mid-day trading today. The stock is gaining momentum after the company announced its sales results for the nine-week period ended December 29, 2012. The company said that its same-store sales during the nine-week period rose 3.3%, led by the U.S. division.