SHANGHAI - Chinese mainland stocks fell on Wednesday, with the country's leading "nifty 50" stocks posting their worst day in six months.

Trading was thin, as investors awaited a likely US interest rate hike later in the session and debated whether China's central bank would follow with modest tightening of its own, as it did in March.

The blue-chip CSI300 index fell 1.3 percent to 3,535.30 points, while the Shanghai Composite Index closed down 0.7 percent at 3,130.67.

The Shanghai SE 50 Index, dubbed China's "nifty 50" index, slumped 1.5 percent in its worst day since mid-December, as investors took profits in blue-chips which had far outperformed the broader market in the past months.

Investors also dumped stocks - mainly big-caps - that are partly owned by Anbang Insurance Group, after the acquisitive company said late on Tuesday its chairman Wu Xiaohui was no longer able to fulfill his duties.

Earlier, Chinese magazine Caijing reported that Wu had been taken away for investigation. Anbang-invested shares - including Financial Street Holdings, China Vanke, China Merchants Shekou, Gemdale and China State Construction Engineering - all dropped sharply.

On Wednesday, economic data that showed the country's fixed asset investment grew more slowly than expected in the first five months of the year, while the pace of new construction starts decelerated sharply in May.

But meanwhile, China's industrial output and retail sales are holding up better than expected and cushioning a broader slowdown.

China's value-added industrial output, an important indicator, expanded 6.5 percent year-on-year in May, official data showed on Wednesday.

In the first five months, industrial output rose 6.7 percent year-on-year.

Reuters - Xinhua