One of the biggest worries that firms expressed were that employees would submit false travel and entertainment expenses, said 65 per cent of respondents.
Executives surveyed by the accountancy firm also raised concerns that their own employees would steal, manipulate or destroy data.
A whopping 83 per cent of respondents said they think cyber security breaches through rogue insiders posed the fastest growing fraud risk.
Paul Walker, EY’s UK head of forensic technology, said: “It is interesting to see that the more ‘low tech’ forms of fraud, such as submitting false receipts, still pose a big concern for many companies as well as the evolving threat of cyber crime.”
Walker added: “The rogue employee is a big threat. The intellectual property assets of an organisation are extremely valuable.”
The use of monitoring tech has doubled over the last two years, with respondents reporting the increasing use of social and web monitoring tools to track down fraudsters.