In Qatar, the share index .QSI fell 0.3%, weighed down by a 1.9% decline in Commercial Bank COMB.QA. By Ateeq Shariff Jan 15 (Reuters) - Stock markets in the Gulf wobbled on Sunday with the Qatari index extending losses for a third session. U.S. Federal Reserve policymakers on Thursday expressed relief that inflation continued easing in December, paving the way for a possible step down to a quarter point interest rate increase when the U.S. central bank meets in just under three weeks.