Fraud committed by those aged 46 and over fell 72 percent, KPMG said, although its value came in higher at £88 million.
Younger conmen are making the most of their technical knowledge and rely on the assumption of the innocence of youth, Hitesh Patel, U.K. forensic partner at KPMG, said in a release.
The survey comes after a number of young professionals have made the headlines for all the wrong reasons.
For example, 34-year-old rogue trader Kweku Adoboli made unhedged trades at UBS between 2008 and 2011 – despite the bank paying him over £300,000 a year. His huge risks lost the bank over $2 billion.
Earlier this year, fraudster Benjamin Wilson was sentenced to seven years in prison for conning investors in his unauthorised investment fund out of £21 million. Wilson set up SureInvestment when he was 24 and it soon became a "Ponzi-style" scheme, according to the U.K.'s Financial Conduct Authority.
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KPMG'S Patel warned that organizations needed to be aware of the shift in the conman profile in order to combat this type of fraud.
"Where once it was the jaded executive who relied on unquestioned seniority and authority to get away with dipping their hands in the till, it seems we are witnessing a changing of the guard," he said in a release.
"It is important for U.K. organisations to recognise that youth doesn't always equal innocence, as a confident and tech savvy generation comes through, adept at circumnavigating conventional controls and staying under the radar."
One case outlined in KPMG's research involved a 30-year-old man who conned people into investing in vintage wine. Over 400 people paid between £20,000 and £2 million in the hopes the wine would increase in value, but the perpetrator spent the money on a new house with a swimming pool and a Lamborghini.
Separately, two 26-year-olds masterminded a scam which involved assigning victims' mobile phone numbers to new SIM cards and repeatedly calling premium-rate numbers. They amassed a total bill of £2.8 million.