Dubai Commercial Bank CBD.DU, the biggest loser in the index, plunged 11.8% as the stock was trading ex-dividend. By Mohd Edrees March 10 (Reuters) - Stock markets in United Arab Emirates closed lower for a fourth straight session on Friday, mirroring losses in crude prices on worries that a tighter monetary policy will affect fuel demand. U.S. Federal Reserve Chair Jerome Powell has warned of higher and potentially faster rate hikes, saying the Fed was wrong in initially thinking inflation was "transitory".