The U.S. Supreme Court turned down a case by business groups seeking to challenge Seattle’s law that raised its minimum wage to $15 an hour. Seattle was the first major U.S. city to implement a big minimum-wage increase after pressure from unions and workers’ advocates. The International Franchise Association and other businesses argued that it was unfair for Seattle to exclude the local franchises of big companies like McDonald’s and Burger King from the contingency that smaller companies have three years to implement the wage hike. The law, which went into effect in April 2015, requires businesses with more than 500 employees nationwide to raise their minimum wage to $15 by 2018, while smaller companies have until 2021 to do so. The high court’s decision means other cities and states that pass similar wage increases must treat franchises as offshoots of big brands.