A US hedge fund lost millions of dollars over a two-month period after hackers installed malware designed to steal trade secrets, according to BAE Systems Applied Intelligence.

It is thought that the criminal intercepted information on high-speed trades which was then relayed to external servers.

Paul Henninger, product director of BAE Systems, said the cyber-attack could be a case of a smaller company spying on the larger firm as the attack began with a simple phishing email on an employee of the unnamed hedge fund.

Although there was no indication that the crime had been reported to the FBI, it was revealed that the company's board noticed the attack immediately and took measures to combat it.

"This was something that was getting reviewed at the board level of this hedge fund precisely because it was having a material impact on performance across the portfolio," Henninger told CNBC.

The culprit, or culprits, is yet to be caught.

A report recently claimed that cybercrime costs businesses nearly half a trillion dollars a year and impacts 150,000 jobs in the European Union.

According to research by McAfee and the Center for Strategic and International Studies (CSIS), businesses across the globe lost around $445bn (£266bn, €327bn) in 2013, while the UK is one of the worst hit nations.

Around 93% of large UK corporations and 87% of small British businesses reported a cyber-breach in 2013.