But the FraudTrack report from accountancy and business advisory firm BDO also found that the volume of cases had risen to its highest level over the same period, with lower-end crimes on the increase.
Report author Kaley Crossthwaite, partner and head of fraud at BDO, found that some firms were choosing to deal with high-value complex fraud outside the judicial system to keep it out of the public eye.
The report showed the total value of fraud in 2014 was £720 million, down 31 per cent on the previous year and the lowest value since the series - monitoring all cases above £50,000 in the UK - began in 2003.
However the number of cases rose to a record 546, from 525 in 2013, with the average value of fraud falling - from £3.3 million in 2012 to £2 million in 2013 and £1.3 million in 2014.
The report found that 402 of the 546 cases had a value of £500,000 or less. These cases made up 74 per cent of fraud by volume but only nine per cent by value.
Ms Crossthwaite said: “2014 was characterised by a large increase in unsophisticated fraudulent activity which was of low value but high in volume.
“The continued growth in number of reported frauds suggests that the police and courts are becoming increasingly effective at convicting low-level fraudulent activity.
“One of the reasons why we have seen the lowest total value of fraud since 2003 is due to a growing trend for high-value complex fraud to be dealt with outside of the judicial system and out of the public eye.
“Companies are increasingly assessing the reputational cost to their brands of a public case against the cost of pursuing the perpetrators of the fraud through the courts.
“This is leading to large numbers of cases being dealt with privately in-house and through alternative remedies.”