An employee comes out of the Baidu headquarters in Beijing. (FAN JIASHAN / FOR CHINA DAILY)

The State Administration for Market Regulation, China's top market regulator, imposed a fine of 500,000 yuan ($78,000) each on 43 cases that violated the Anti-Monopoly Law on Saturday.

Companies involved in the cases, including Baidu Inc, Alibaba Group and Tencent Holdings, were found to have not declared the concentration of business operations according to the law, the SAMR said on its website on Saturday.

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Most of the 43 cases were related to mergers and acquisitions, such as Alibaba's acquisition of navigation firm Amap and Tencent’s acquisition of China Medonline Inc.