(Yicai Global) March 7 -- A CNY999 million (USD150 million) lawsuit has thrown a spanner in the works for Bull Group, a socket maker currently eying an initial public offering on the Chinese mainland.

Jiangsu Tongling Technology has accused the Zhejiang province-based firm of infringing on two of its patents, 21st Century Business Herald reported today, citing an employee from Bull Group's securities department. A lawyer is handling the case and the suit has not affected the company so far, he added.

Bull Group, founded 1995, began its IPO application in September and was hoping to raise up to CNY4.9 billion to invest in its core business -- making sockets, wall switches and light-emitting diodes. The firm has more than 300 patents of its own in China and sells to over 30 countries.

Tongling, which researches and develops electric switches and safety sockets and has 87 patents in the US, Canada and China, believes the defendant used two of its electronics charters for an invention and a utility model and has requested the courts order Bull Group to cease infringing on the intellectual property immediately and pay damages.

If Tongling wins the case, it would be the largest successful patent infringement suit in recent years. The amount it hopes to claim is equal to Bull Group's 2015 profit and slightly behind its CNY1.4 billion and CNY1.3 billion earned in 2016 and 2017.

Bull Group received court documents on Dec. 25 and the case is still at trial, the source said, a while Tongling receptionist said company executives were away on business and she was unclear on the current situation.

Editor: James Boynton