Share prices closed the morning lower due to the general perception that the outlook for Wall Street will remain unstable, in spite of its strong gains overnight, dealers said.
They said investors continue to be concerned about the US economic outlook, which will have a direct impact on the local economic recovery.
Investors were also awaiting interim results due this afternoon from tom.com, Hong Kong Electric and Swire Pacific.
The Hang Seng index closed the morning down 61.29 points or 0.61% at 9,916.45, off a high of 9,997.17 and a low of 9,895.28.
The Hang Seng August contract was at 9,830 points.
The China Enterprises index was up 0.27 points at 1,912.99 and the CAC index 1.74 points higher at 1,096.07.
The GEM index was down 1.76 points at 144.24.
Kitty Chan, associate director of Lippo Securities, said investors were worried about the outlook for Wall Street, which was seen as having merely posted short-term technical gains overnight.
"Investors are also worried about the US economic outlook ... if the US economy continues to slow down, it will hinder the economic recovery in Hong Kong," she said.
The Hang Seng Index is likely to remain range bound at 9,600-10,000 points in the short term, she said, adding that investors will continue to digest the spate of earnings news.
In the property sector, Cheung Kong was down 0.75 at 57.75, Sun Hung Kai Properties flat at 54.00 and Henderson Land 0.50 lower at 27.75.
Of the banks, HSBC dropped 1.0 to 86.25, Hang Seng Bank fell 1.50 to 85.25 and BOC Hong Kong was unchanged at 8.30.
Wing Hang Bank was up 0.05 at 26.30 ahead of the release of its first half results.
Of the telecommunications stocks, China Mobile was up 0.05 at 21.40, China Unicom down 0.05 at 5.25, PCCW 0.02 lower at 1.50 and Hutchison Whampoa shed 0.50 to 53.00.
Of the H-shares, China Eastern Airlines was down 0.01 at 1.24, China Southern flat at 2.875 and Zhejiang Expressway dropped 0.05 to 2.40.
Beijing North Star was down 0.08 at 1.07 after it called off the issue of A-shares and may now issue H-shares to raise funds, dealers said.
Among red-chips, TCL International lost 0.04 to 1.88, COSCO Pacific fell 0.05 to 5.40, while Founder was down 0.01 at 0.71.
After the release of their financial results, Huaneng Power was up 0.10 at 6.00 and Legend was 0.05 higher at 2.80.
On the GEM Board, CK Life Sciences lost 0.05 to 1.81, Hongkong.com was flat at 0.206 and Sunevision was down 0.03 at 1.04.
Tom.com lost 0.075 to 2.775 prior to the release of its first half results.
Hycomm Wireless was up 0.01 at 0.096 on a technical rebound.