In a move that reflects the growing demand in the market for data leak prevention solutions, security software maker Symantec has announced the acquisition of privately held data loss-prevention company Vontu for $350 million.

Symantec’s acquisition comes after rival McAfee last month announced plans to acquire data encryption and leak prevention vendor SafeBoot for $350 million. Vontu’s data monitoring and prevention software discovers sensitive information on the network and then prevents it from leaking out on laptops, storage devices or through the internet. Symantec said the software will complement its Endpoint Protection 11.0 corporate antivirus and will also be integrated with its archiving and backup products so that “rules and decisions about what sensitive data can be backed up and where it can be stored can be put in place.”

Although the market for data loss prevention is still relatively small, it has undergone significant consolidation in the past few years and is estimated that companies will spend more than $3.2 billion by 2011 on software to prevent the increasingly common identity theft and data loss problems, according to research firm IDC.