China's market regulator said on Friday it has fined 12 companies related to 10 deals that demonstrated illegal monopolistic behaviour.
The State Administration for Market Regulation (SAMR) said in a statement on Friday that the companies include Baidu Inc, Tencent Holdings, Didi Chuxing, and a ByteDance-backed firm.
Companies were fined 500,000 yuan ($77,078.42) each, according to the statement.
Baidu, Tencent, ByteDance and Didi did not immediately respond to requests for comment.
China has stepped up its scrutiny of the country's internet giants in recent months and has in particular cited concerns over monopolistic behaviour and potential infringements of consumer rights.
The SAMR has fined Alibaba, Tencent-backed China Literature and other firms for not reporting deals properly for anti-trust reviews.