The State Administration for Industry and Commerce (SAIC) has launched an anti-monopoly investigation into Microsoft Corp.'s business on the Chinese mainland, it confirmed on July 29.

According to a statement made by the SAIC, the investigation involves Microsoft China Co. Ltd., and three of its branches in Shanghai, Guangzhou in Guangdong Province and Chengdu in Sichuan Province. The administration said that the firm had not fully disclosed anti-competition information about its Windows operating system and Microsoft Office applications as required.

Inspectors are investigating a Microsoft vice president and several senior managers, and have made copies of the firm's financial statements and contracts, the SAIC said.

The administration has seized documents, e-mails and other data from Microsoft's computers and servers. It has not been able to complete its investigation because key personnel of Microsoft are not in China or cannot be contacted, according to the statement.

In June last year, the SAIC investigated complaints from enterprises that Microsoft had used tie-in sales and verification codes in its Windows operating system and Microsoft Office applications, causing software incompatibility issues.

Microsoft failed to fully disclose information as required by the SAIC about such complaints in its reports submitted to the regulator, and may have breached China's Anti-Monopoly Law, the statement said.

Under the law, companies or individuals should not abuse their market dominance to exclude or restrict competition and should be supervised by the public.