China's bureau for regulating monopolies has fined three leading internet companies for failing to disclose past deals under the country's newly-drafted anti-monopoly laws.

The State Administration for Market Regulations announced on Monday it has fined e-commerce giant Alibaba Investment Ltd, e-book site China Literature Ltd and logistics player Shenzhen Hiv Box Technology Co Ltd 500,000 yuan ($76,459) each for not seeking regulatory approvals prior to their respective acquisitions

The decisions were made after investigations on the three deals, namely Alibaba's purchase of Intime Retail, China Literature buying into New Classics Media, and Hiv Box acquiring a subsidiary of China Post, all of which "failed to ipso jure declare" the prospective monopolistic status upon the acquisition, the government agency said in a written Q&A release on its website.

"While competition on the platform economy has exhibited some new features, the internet sector is not a 'land beyond law'," the release said. "All companies should strictly abide by anti-monopoly laws and regulations and maintain fair market competition. Only in this way can we ensure the healthy development of the entire industry."

Meanwhile, the investigations concluded that the three acquisitions have not de facto eliminated or restricted competition. Therefore, the deals are not deemed as breaching anti-competitive rules and the companies are not required to revoke these acquisitions, the authorities said.