Wal-Mart has settled Department of Labor claims that many workers were mis-classified as exempt. Exempt workers are not paid overtime. 4500 workers were part of the suit. The settlement includes $4.8 million in unpaid overtime wages. See Workplace Prof Blog. As Workplace Prof mentions, Wal-Mart seems to always be in violation of one workplace law or another. Civil penalties of over $463,000 were also assessed due to the repeated nature of these violations. See DOL news release.
The DOL investigation was regarding vision center managers and asset protection coordinators for Wal-Mart.