Following a trend that began in cities across the country, in August of 2015, the City of St. Louis increased its minimum wage. The Minimum Wage Ordinance operated incrementally, first increasing the minimum wage to $8.25 per hour, with further increases over a three-year period. At the time the Ordinance was passed, the Missouri state minimum wage was $7.65.

In response, several businesses and employer groups filed suit in the City of St. Louis Circuit Court, seeking to invalidate the Ordinance. Though the trial court judge disagreed with the plaintiffs on several points, he ultimately invalidated the Ordinance in October 2015. Both sides appealed.

On February 28, 2017, the Missouri Supreme Court reversed the trial court decision and ruled that the Ordinance is valid, allowing the City to proceed with the increases in its minimum wage. The Court majority analyzed the Ordinance in conjunction with several state statutes, holding one unconstitutional, and finding that none invalidated the Ordinance.

In its key holding, the Court found that the State minimum wage statute merely set a "floor below which an employee cannot be paid," and that nothing in State law set a maximum wage or prohibited a municipality from setting a higher minimum wage. Accordingly, the Court determined that the Ordinance was not preempted by or in conflict with the State minimum wage law. The Ordinance cleared its final hurdle when the Court observed that yet another state law, which explicitly prohibits a municipality from mandating a minimum wage, was enacted too late to stop the City's plans.

Though the Ordinance would have incrementally increased the minimum wage over time, its sudden revival means that the minimum wage in the City of St. Louis is now $10.00 per hour, with a raise to $11.00 per hour slated for January 1, 2018. The Mayor's office has indicated that it will work with local businesses on a grace period to allow for an adjustment to the new minimum wage. At this time, however, it is unclear when businesses will have to conform to the requirements of the newly-validated Ordinance, or what potential penalties will be in place for violations.