(Yicai Global) May 13 -- Bull Group’s shares sank after the leading seller of power sockets and strips on China’s Tmall e-commerce site said antimonopoly regulators are investigating the company.

Pulling back from a slump of as much as 9.7 percent earlier in the day, Bull’s stock price [SHA: 603195] closed down 4.6 percent at CNY181.65 (USD28.14). The broader Shanghai Composite Index came off almost 1 percent.

The Zhejiang bureau of the State Administration for Market Regulation is looking into whether the electrical equipment maker signed an unfair agreement with its trading partner, Bull said in a statement yesterday.

The Zhejiang-based company said it will cooperate with the authorities and added that the probe should not affect daily operations.

China is investigating a number of leading businesses in a nationwide crackdown on unfair market practices. Regulators recently examined internet giants Alibaba Group Holding and Tencent Holdings on suspicion of monopoly conduct. Both were subsequently hit with fines, a record USD2.8 billion in Alibaba’s case. Bull is the latest to come under the microscope.

In the first quarter, Bull logged a nearly fourfold increase in net profit to CNY607 million (USD94 million) from a year ago, according to its earnings report. Its revenue jumped 87 percent to CNY2.6 billion (USD402.9 million). Profit and revenue last year were little changed at CNY2.3 billion and CNY10.1 billion (USD1.6 billion).

Editor: Emmi Laine, Xiao Yi