As of this writing, it is unknown why Microsoft is being targeted by the China's State Administration for Industry and Commerce agency, but speculation is that it relates to earlier statements by the government that the latest version of the company's Windows operating system is not secure.
According to Reuters and the South China Morning Post, the State Administration for Industry and Commerce raided Microsoft offices in Beijing, Shanghai, Guangzhou, and Chengdu today. In May the Chinese government banned government institutions from using Windows 8 saying that it was vulnerable to security breaches that could open computer systems that use it to spying.
Microsoft's China operations did not have a lot to say about the raids, save that it was cooperating with authorities.
In a statement on Monday, Microsoft said, "We aim to build products that deliver the features, security and reliability customers expect, and we’re happy to answer the government’s questions."
Source: GIGA OM