"While about half of large employers offered an HDHP in 2009, nearly three out of four did so in 2014. In addition to saving on health care costs, HSA-HDHPs may help employers avoid triggering the so-called 'Cadillac Tax.' ... To achieve significant savings, an employer may need to completely replace its health plan options with an HSA-HDHP.... Employees may adapt to the change more easily if it is phased in over several years."