How do the biggest corporations earn such massive profits? They’d like you to think it’s the result of delivering a superior product or service. But one part of that story is years of wage theft from their employees.

Good Jobs First, a policy resource center focused on government and corporate accountability, recently carried out a year-long investigation into wage theft by large employers, compiling information from collective action lawsuits brought by groups of ripped-off workers, as well as actions brought by the department of labor and state-specific regulatory agencies. The results, brought together in a report released this week titled Grand Theft Paycheck: the Large Corporations Shortchanging their Workers’ Wages, are eye-opening: 4,220 cases since the turn of the millennium with penalties totaling $9.2 billion.

You might think wage theft is a crime only small or fly-by-night businesses commit. In reality, just about every well-known corporate name made its way onto the list of nearly five hundred companies that have racked up penalties worth more than $1 million. Bringing up the rear is Southwest Airlines with one case worth $1 million. At the very top (by far) is Walmart, with a staggering $1.4 billion worth of settlements and fines from only thirty-six cases.