Aetna announced one of its largest pay hikes recently. CEO Mark Bertolini says he believes it largely could pay for itself by making workers more productive. Courtesy of Aetna hide caption

itoggle caption Courtesy of Aetna

McDonald's announced this week that it will pay workers in its company-owned stores $1 more per hour than the local minimum wage. Wal-Mart, Target and the parent company of Marshalls and TJ Maxx have also promised to boost wages for their lowest-paid workers this year. Lucy Nicholson/Reuters/Landov hide caption

itoggle caption Lucy Nicholson/Reuters/Landov

Fast-food workers in Los Angeles march in August 2013 to raise the minimum wage to $15 an hour. Similar protests around the country have been organized by labor unions. Nick Ut/AP hide caption

itoggle caption Nick Ut/AP

A New York Stock Exchange trader works on the floor on Dec. 17. Stocks rose nearly 300 points after the Federal Reserve announced it plans to begin raising interest rates next year. Andrew Burton/Getty Images hide caption

itoggle caption Andrew Burton/Getty Images

Nissan workers at a plant in Canton, Miss. The auto company received financial incentives, including tax relief, from the state for the factory. Rogelio V. Solis/AP hide caption

itoggle caption Rogelio V. Solis/AP

Demonstrators from the Fast Food Forward rally protest Thursday outside a Wendy's restaurant in New York City. Mary Altaffer/AP hide caption

itoggle caption Mary Altaffer/AP