Shares closed down on Wednesday, with futures trade appearing to show that support for mainland stocks may be losing traction.

China CSI300 stock index futures for January fell 3.3 percent, to 3,259.2 points, which was still 29.4 points above the current value of the underlying index but down nearly 7 percent over the past three trading days. Other futures contracts also declined.

The CSI300 index, which covers the largest listed companies in Shanghai and Shenzhen, slid by 2.8 percent to 3,230.39 points, while the benchmark Shanghai Composite Index lost 1.9 percent to end at 2,972.53 points, dropping below 3,000 - considered a sentiment support level - for the first time since Dec 17.