* SSEC -0.2 pct, CSI300 -0.3 pct, HSI +0.5 pct
* Property boom may be losing steam - economist
* Bank stocks fall as chance of stimulus fades
By Nathaniel Taplin
SHANGHAI, Sept 1 (Reuters) - China stocks fell on Thursday as investors sold real estate stocks following official August purchasing managers' index (PMI) data showing activity slowing in the construction sector.
Property stocks led indices lower with the Shanghai Composite property sub-index down 1.6 percent by midday.
"While the official non-manufacturing PMI remains strong, it did soften from 53.9 to 53.5 last month. This was entirely due to a fall in the construction sector sub-index," wrote Julian Evans-Pritchard, China economist at Capital Economics in Singapore.
"The stats bureau has blamed the drop on disruptions due to flooding and unusually hot weather but it may also be a sign that the recent property boom is starting to run out of steam," he said.
Finance stocks also slipped as the strong official manufacturing PMI, which unexpectedly moved back into positive territory in August, appeared to dampen the chances of further monetary stimulus. The CSI 300 financial services sub index dropped 0.6 percent.
The CSI300 index fell 0.3 percent, to 3,318.17 points at the end of the morning session, while the Shanghai Composite Index lost 0.2 percent, to 3,080.87 points.
China CSI300 stock index futures for September fell 0.4 percent, to 3,293.4, or 24.77 points below the current value of the underlying index.
The Hang Seng index added 0.5 percent, to 23,094.52 points.
Index heavyweight HSBC Holdings gained 2.7 percent after Deutsche Bank raised its target price and the bank was a co-bookrunner for a special drawing rights denominated bond in China.
The Hong Kong China Enterprises Index gained 0.5 percent, to 9,584.83.
The index measuring price differences between dual-listed companies in Shanghai and Hong Kong stood at 124.65.
A value above 100 indicates Shanghai shares are pricing at a premium to shares in the same company trading in Hong Kong, and vice versa.
The northbound quota for the Hong Kong-Shanghai Stock Connect, currently set at 13 billion yuan, saw net inflows of 13.00 billion yuan.
Total volume of A shares traded in Shanghai was 7.98 billion shares, while Shenzhen volume was 9.32 billion shares.
Total trading volume of companies included in the HSI index was 0.8 billion shares.
Editing by Richard Borsuk