Mercenary hackers are stealing billions of dollars of intellectual property and technology secrets every year from American firms, according to the cybersecurity consultancy Taia Global.
The groups carrying out so-called Espionage-as-a-Service (EaaS) attacks are said to range in size and skill, and can be carried out by anybody from an amateur to an ex-spook.
Jeffrey Carr, chief executive of Taia, said: "That they are rarely discovered is due in part to their skill level and in part to being misidentified as a state actor instead of a non-state actor if they are discovered.
"The low risk of discovery, frequent misattribution to a nation state, and growing demand of their services ensures that the EaaS threat actor will flourish in the coming 12 to 24 months."
The theft of intellectual property is estimated to cost the US $300bn (£200bn) a year, according to a report by the IP Commission, and frequently targets defence firms.
An indictment filed by the FBI last year against Su Bin, an alleged hacker from China, accused him of targeting information about aeroplanes, including the F-35, C-17 and F-22, adding that he had two accomplices which were still at large.
