Macy's M.N on Monday delayed its third-quarter results after finding that an employee hid as much as $154 million in expenses over years, instead issuing preliminary sales figures that fell short of Wall Street expectations.

An internal investigation revealed that a single employee intentionally concealed these expenses over nearly three years.

Macy's reported weaker-than-expected preliminary sales for the fiscal third quarter and said it's delaying the release of its quarterly earnings results after it discovered an up to $154 million accounting-related issue.