Cyber security company FireEye has acquired privately-held cyber incident response firm Mandiant in a deal that could be worth about $1bn (£608m).
The transaction closed on December 30, 2013.
US firm Mandiant, which has been a partner of FireEye's since April 2012, is best known for releasing a report citing a secret branch of China's People's Liberation Army (PLA), dubbed unit 61398, as the source of a campaign of espionage against 141 corporations in 20 industries in the US.
It has also been selected by the Communications Electronics Security Group (CESG) and the Council of Registered Ethical Security Testers (CREST) as one of the first companies to be certified under the government's Cyber Incident Response scheme, which ultimately aims to help organisations deal with cyber-attacks.
FireEye claims that Mandiant advises more than a third of the Fortune 100, and has responded to hundreds of high-profile security incidents, enabling it to "bring deep security and incident response expertise to FireEye".
The cyber security firm hopes that by working even closer with Mandiant, it can develop its intelligence to detect and prevent attacks on networks and on endpoints.
"Organisations today are faced with knitting together a patchwork of point products and services to protect their assets from advanced threats," said David DeWalt, CEO of FireEye.
"Together, the size and global reach of FireEye and Mandiant will enable us to innovate faster, create a more comprehensive solution, and deliver it to organisations around the world at a pace that is unmatched by other security vendors," he claimed.
The companies' products have been integrated since February 2013. Kevin Mandia, Mandiant's founder and CEO prior to the acquisition, has been appointed chief operating officer of FireEye.