Dec. 11 (Bloomberg) -- Microsoft Corp., the world's biggest software maker, filed 52 lawsuits in 13 countries against resellers who allegedly sold counterfeit software over the Internet.

Fifteen of the lawsuits involve software traced to a commercial counterfeit-software syndicate that was broken up this year by Chinese authorities, the Redmond, Washington-based software maker said today in an e-mailed statement. Microsoft also referred 22 cases to law enforcement officials in 13 countries, according to the statement.

Piracy costs the PC software industry about $40 billion a year in lost sales, Microsoft said. Counterfeit software, which is designed to look like genuine Microsoft products to fool consumers, can contain harmful viruses and spyware, the company said.

``Every day, software pirates around the world put countless consumers at risk by selling defective counterfeit software through Internet marketplaces,'' Microsoft Associate General Counsel David Finn said in the statement.

In addition to 15 cases brought in the U.S., the suits were filed in Belgium, Canada, France, Germany, China, India, Ireland, Italy, the Netherlands, Turkey, South Africa and the U.K.

To contact the reporter on this story: Edvard Pettersson in Los Angeles at epettersson@bloomberg.net.

Last Updated: December 11, 2007 19:50 EST