* HSI -0.7 pct, H-shares -0.8 pct, CSI300 +0.4 pct
* Shanghai volume robust, new A-share accounts last week at 2-mth high
* Zoomlion tumbles despite denial of alleged false sales data
By Clement Tan
HONG KONG, May 29 (Reuters) - China shares are headed for a fourth-straight daily gain in robust bourse volumes on Wednesday, powered by strength in the real estate and auto sectors that is helping mainland markets outperform Hong Kong.
At midday, the Hang Seng Index was down 0.7 percent at 22,767.4 points, while the China Enterprises Index of the top Chinese listings in Hong Kong shed 0.8 percent. Both are set for their first loss in three days.
The Shanghai Composite Index and the CSI300 of the leading Shanghai and Shenzhen A-share listings each rose 0.4 percent. If gains hold, this would be their fourth-straight daily gain.
They have rebounded 7.1 and 8.3 percent, respectively, from May lows but are still some way off February highs. The Securities Times reported on Wednesday that the number of new A-share trading accounts last week hit a two-month high, a sign that retail investors are returning.
The 21st Century Business Herald reported insiders as saying that initial public offerings in the mainland, suspended since late last year, could resume in the middle of August.
"Property has been a key call for me and I am sticking with it, the supply shortage has kept sales quite strong so far and it looks like Beijing is intervening to keep land prices down," said Hong Hao, chief strategist at Bank of Communication International Securities.
"But I don't quite share their enthusiasm for reforms, which are going to be harder to push through than people think. Investors should be prepared for increased volatility in the next two weeks," Hong added.
On Wednesday, price movements for Chinese property shares listed in Hong Kong and the mainland diverged. Poly Real Estate climbed 1.5 percent in Shanghai, while China Overseas Land fell 1.7 percent in Hong Kong.
The official China Securities Journal newspaper reported on Wednesday, citing insiders, that Beijing may expand a property tax trial to more cities and will focus on taxing new construction and extra space in units where the area per resident is above average.
Chinese automakers were also strong. SAIC Motor climbed 2.8 percent in Shanghai, while in Shenzhen, FAW Car jumped 8.2 percent and Warren Buffett-backed BYD Co Ltd spiked 7.7 percent.
Zoomlion Heavy Industry was a key underperformer in both markets, sliding despite an official rejection of recent media reports that China's second-largest construction equipment maker provided false sales data.
Trading for the first time this week, Zoomlion tumbled 5.4 percent in Hong Kong to near its record low set in April. It is now down 34 percent on the year, compared to the 5 percent slide on the H-share index. Its Shenzhen listing slid 2.2 percent.