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

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Lori Lomas, an insurance agent with Feather Financial in Quincy, Calif., has noticed that her clients in San Francisco have many more health carrier options than her mountain neighbors. Pauline Bartolone for KXJZ hide caption

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Insurance companies negotiate with hospitals and doctors the price of every treatment, procedure and medical service. That price differs from hospital to hospital — even health plan to health plan. Vincent Wartner/Science Source hide caption

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Maritza Martinez worked with an insurance agent at a kiosk in a Miami mall to find the right health insurance plan for 2014. Joe Raedle/Getty Images hide caption

toggle caption Joe Raedle/Getty Images