HONG KONG, Jan 23 (Reuters) - China shares were knocked off two-week highs on Thursday, led by the financial sector after a private preliminary survey showed factory activity shrank slightly in the world's second-largest economy in January.
The CSI300 of the largest Shanghai and Shenzhen A-share listings ended down 0.5 percent at 2,231.9 points. The Shanghai Composite Index also slipped 0.5 percent as volumes declined 15 percent from Wednesday.
On Wednesday, both indexes had their biggest daily gain in two months and reached their highest closes since Jan. 3.
The ChiNext Composite Index of startups in mainly nascent industries listed in Shenzhen outperformed on Thursday, soaring 2.2 percent to another record closing high.
The flash Markit/HSBC Purchasing Managers' Index fell to 49.6 in January from December's final reading of 50.5, dropping below the 50 line which separates expansion of activity from contraction for the first time in six months.
Money rates crept higher on Thursday despite a second cash injection for the week by the People's Bank of China. In the biggest weekly net injection since February 2013, it put in a total of 375 billion yuan ($61.97 billion).
($1 = 6.0513 Chinese yuan)
(Reporting by Clement Tan; Editing by Richard Borsuk)