Hong Kong CNN Business  — 

China is bringing the regulatory hammer down yet again on some of the country’s largest tech firms.

Alibaba, Tencent, Baidu and other companies were all slapped with fines over the weekend for violating antitrust laws, the State Administration of Market Regulation (SAMR) said in a statement.

SAMR listed 43 separate violations, with some offenses dating back as far as 2012. The penalty for each fine is 500,000 yuan ($78,000).

“The cases announced this time are all transactions that should have been declared but not declared in the past,” SAMR said in its statement.

The market regulator has spearheaded a yearlong campaign against Big Tech in China. The totals announced Saturday are small in comparison to some of the marquee penalties levied earlier this year, including an 18.2 billion yuan ($2.8 billion) record fine that Alibaba (BABA) was ordered to pay. At the time, antitrust regulators said they had concluded that the online shopping giant had been behaving like a monopoly.

Shares of Alibaba, Tencent (TCEHY) and Baidu (BIDU) were all slightly lower in Hong Kong on Monday following the announcement. Baidu (BIDU) fell the most, 2.1%, while Tencent (TCEHY) slumped 0.3%.

Alibaba fell 1.6%. The company on Friday plunged nearly 11% in its steepest decline since listing in Hong Kong in November 2019. The tech giant warned last week of weaker growth this year as China’s economy slows and Beijing continues its regulatory crackdown. (Alibaba also trades in New York.)

— CNN’s Beijing bureau contributed to this report.