The three companies have received investigation notices from the China Securities Regulatory Commission under its new chairman Xiao Gang.

Shanghai-listed Weifang Beida Jade Bird Huaguang Sci-Tech Co Ltd - a software provider based in Shandong province - received the investigation notice on Wednesday, although the commission still has to say on what ground the investigation was launched.

The company hit the 10 percent daily price-increase limit for three consecutive days last week.

It reported a net profit of 37.78 million yuan ($6.01 million) for 2012, after being hit by annual losses since 2010. On March 7, the Shanghai Stock Exchange removed its delisting-risk warning for the company.

After receiving the notice on Wednesday, the share price of Jade Bird Huaguang still rose 10 percent on Thursday. The shares were at 5.35 yuan on Monday, the same price as on Friday.

The second company is Sichuan-based Huasu Holding Co Ltd. The company received its notice on Thursday and its stock price fell 10 percent that day.

The commission did not disclose any specific reasons for the investigation.

According to financial market insiders, the company is suspected of selling State-owned stocks at prices below valuation and of irregularities in its financial report.

The firm was suspected of illegal information disclosure in January, according to an announcement from Sichuan's provincial securities watchdog.

On Monday, the company's stock price was 10.23 yuan, up 1.49 percent.

The third company is Shenzhen-based Hirisun Technology Inc, which received the notice on Thursday.

According to a source at a domestic brokerage firm, the investigation might be linked to financial fraud and dissemination of information with inaccurate facts and figures.

The company's shares were at 8.72 yuan on Monday, down 0.57 percent.