* CSI300 -0.2 pct; SSEC -0.1 pct; HSI +0.9 pct
* Market sentiment calms, but trading volume shrinks
* state banks suspected of yuan intervention
SHANGHAI, Sept 11 (Reuters) - China's major stock indexes ended Friday morning slightly lower, bobbing in and out of positive territory as investors awaited more data for clues on the health of the economy.
Hong Kong stocks rose slightly by midday.
China's blue-chip CSI300 index fell 0.2 percent to 3,352.66 points at lunch time, while the Shanghai Composite Index lost 0.1 percent to 3,195.54 points.
The indexes are set to end the week around where they were a week earlier, suggesting the market has calmed following fresh supportive measures announced recently, including further trading restrictions on derivatives, and a proposed "circuit breaker" mechanism.
But trading wad thin, with weekly volume in the CSI300 shrinking to the lowest since February.
"The market was rather stable in the morning session with investors choosing to stay on the sidelines," wrote Gerry Alfonso, director at Shenwan Hongyuan Securities Co.
Fresh economic data showed that the risk of deflation in China is growing, as policymakers tried to reassure markets that the economy can stay on track and state banks were suspected of intervening in offshore markets to bolster the yuan.
Most sectors fell, with small-caps outperforming blue-chips.
The CSI500 index of China's small companies, and Shenzhen's start-up board ChiNext ended Friday morning in positive territories.
In Hong Kong, the Hang Seng index was up 0.9 percent, to 21,746.95 points, while the Hang Seng China Enterprises index was 0.8 percent firmer.
Sun Hung Kai Properties shares rose 4.2 pct, heading for their biggest single-day percentage gain since Oct. 24, 2011, after the developer said it was confident of achieving its HK$32 billion Hong Kong property sales target for the fiscal year. (Reporting by Samuel Shen and Pete Sweeney; Editing by Simon Cameron-Moore)