How many government organizations does it take to investigate one company? In Walmart's case, at least three.

On Tuesday, the Department of Labor announced that Walmart had agreed to pay $4.83 million in back wages and damages to employees it had illegally denied overtime, following an agency investigation. More than 4,000 workers, all vision center managers or asset protection coordinators, will receive money from the settlement.

"Thousands of employees will see money put back into their pockets that should have been there all along," said Nancy J. Leppink, deputy administrator of the Labor Department's wage and hour division, in a statement.

Walmart is also being investigated by the Department of Justice and the U.S. Congress over allegations that it systematically bribed Mexican officials in order to obtain permits for new stores.

While all U.S. workers are legally entitled to overtime when they work more than 40 hours a week, certain salaried managerial employees in "executive, administrative or professional" roles, are exempt from this provision under the Fair Labor Standards Act. Prior to 2007, Walmart considered its vision center managers and asset protection coordinators exempt, a policy the Department of Labor now calls a "misclassification."

"When the issues resolved today were initially raised, we took them seriously and fully cooperated with the Department of Labor to make sure they were corrected in 2007," wrote Greg Rossiter, a Walmart spokesman, in an email statement. "We adjusted our pay practices at that time and determined that back wages should be paid for the associates involved."

"We have agreed on a fair settlement amount for the associates that trained for the role of Asset Protection Coordinator (APC) and associates in the role of Vision Center Manager (VCM), and we are pleased to have resolved this matter," he added.

The asset protection coordinators will receive an average of $290 a person, while the vision center managers will receive an average of $2,300 each, according to Rossiter.

Walmart has long been plagued by complaints, investigations and lawsuits over its overtime policies. In 2008, the company agreed to pay as much as $640 million to settle 63 federal and state class actions that charged the company with refusing to pay overtime, as well as other types of wage theft.

In a separate case in Massachusetts in 2009, the company paid $40 million -- the largest wage and hour class-action settlement in the state's history -- to settle a suit that accused it of refusing to pay overtime, denying employees rest breaks and tampering with time sheets.

And in 2007, through another Department of Labor settlement, Walmart paid $33.5 million in back wages to 86,680 workers, many of them managers who were denied overtime.

Employees at Walmart's warehouses have also filed lawsuits, claiming their wages were stolen. In California and Illinois, workers allege that Walmart's warehouse operators, who have exclusive contracts with the retailer, paid them for fewer hours than they worked.

The most recent Department of Labor settlement also included a civil penalty of $463,815 that "stem[s] from the repeat nature of the violations," according to an agency news release.