Russia's central bank raised its key interest rate by a higher than expected 200 basis points to 15% on Friday, hiking borrowing costs for the fourth meeting running in response to a weak rouble and stubborn inflation pressure. The central bank has now raised rates by 750 basis points since July, including an unscheduled emergency hike in August as the rouble tumbled past 100 to the dollar and the Kremlin called for tighter monetary policy.