For years, Macy’s Inc. touted its ability to boost profits by cutting delivery costs and trimming other expenses on calls with Wall Street analysts. Then on Monday, the department store chain surprised investors by revealing that those very costs had become the source of an internal investigation into what the company has described as a multimillion-dollar employee plot to manipulate the metrics.

Macy’s announced Monday that a single employee was responsible for so many accounting irregularities that the company was forced to delay its quarterly earnings report, which the retailer had planned to release Tuesday.

Macy’s is delaying its third-quarter earnings release and conference call because of a single employee’s intentional accounting errors.