China's manufacturing activity growth slowed to a three-month low in December, final results of a business survey by Markit Economics and British bank HSBC Ltd., showed Thursday. The HSBC China Manufacturing Purchasing Managers Index (PMI), a gauge of nationwide manufacturing activity of the world's second-biggest economy, slipped to 50.5 from November's final reading of 50.8 on a 100-point scale, unchanged from a preliminary reading two weeks ago. The index marked the weakest expansion since September, but still stayed above the key 50 percent line. A PMI reading above 50 percent indicates growth from the previous month, while a reading below 50 represents contraction in China's manufacturing sector. The index is a closely watched barometer of the health of the Chinese economy. "The moderation of December's final HSBC China Manufacturing PMI was mainly due to slower output growth," HSBC economist Qu Hongbin said in a statement accompanying the report. "However, the final PMI sustained the fifth above-50 reading in a row thanks to a steady increase of new orders. The recovering momentum since August 2013 is continuing into 2014, in our view. With inflation still benign, we expect the current monetary and fiscal policy to remain in place to support growth," Qu added. The HSBC final PMI came a day after China's National Bureau of Statistics said its official PMI slowed to 51.0 last month, down from November's 51.4. The government index marked the 15th consecutive month of growth, but declined from the previous month for the first time since June