Internal theft is one of the greatest concerns for retailers, and it is on the rise.

The U.S. Retail Fraud Survey 2015 has revealed that employee theft, of both stock and cash, is now one of the top three concerns for retailers.

The survey reveals that alongside online fraud and return fraud, internal theft is a major area of concern for retailers and the biggest area of store loss. Concern about employee theft of stock has risen from 18% in 2012 to 38% in 2015. While recognizing that cash theft is a problem, the study reveals that it has only increased from 24% to 26% this year and comes in second, administrative third with 23% and shoplifting fourth with 11%.

Published by Retail Knowledge and sponsored by intelligent cash handling experts Volumatic, the U.S. Retail Fraud Survey 2015, now in its third year, is the most extensive report into the systems, processes and strategies of the U.S.’s top retailers.

“North Americans are more up front about insider fraud than their retail colleagues in the UK,” said Paul Bessant, founder of Retail Knowledge, and commissioner of the Survey. Its UK sister publication noted that internal loss in the UK ‘may be under reported’ and comes in second as a concern, after outsider shoplifting.

“Cash and merchandise losses caused by internal fraud are only part of the story. When you factor in the costs and time spent in investigations and disciplinary procedures, not to mention the damage done to internal morale and external reputation – the cost of insider fraud can be up to three times as much as the original losses incurred,” added James Harris, commercial director of Volumatic, Survey sponsor.