Over a third of IT administrators believe highly sensitive company information has been handed to competitors, a survey has revealed.
Customer databases, research and development plans are the most sought-after types of information.
Former employees were cited as the most likely sources of this abuse of trust, according to 37% of UK and US IT professionals polled by security firm Cyber-Ark.
Insider sabotage has increased to 27%, up from 20% in 2009.
Human error was cited as the next most likely cause of intellectual property loss, followed by external hacks and the loss of mobile storage devices.
The results are little different to the previous year's survey, indicating that more needs to be done to protect companies' most valued assets, said Cyber-Ark.
This includes access control systems to limit the loss of data through human error by allowing access to information only when users need it, the firm said.
The research confirmed that snooping continues to rise in organisations in the UK and the US.
Some 41% of respondents admitted using administrative passwords to snoop on sensitive or confidential information, an increase from 33% in 2008 and 2009.
Despite the rise, the survey found organisations are trying to curb snooping and installing stronger controls to prevent these incidents.
Only 61% of respondents said they could circumvent controls, down from 77% in 2009. Over two thirds (70%) said their use of privileged accounts is monitored.
But this means one third are still turning a blind eye to what is happening in their networks, failing to meet regulatory and compliance requirements.
Adam Bosnian, executive vice present Americas and corporate development at Cyber-Ark, said it is the organisation's responsibility to protect its sensitive information.
"Failing to do so makes the company as bad as those who are abusing their privileged positions," he said.