The 2017 version of the answer to this question has just been released by the trustees of both pools of money. According to an article in Marketwatch:
Members who receive Medicare Part D benefits through United American (PDP) will see no benefit changes in 2016. All benefits, formulary and the pharmacy network will remain consistent in 2016, yet will be administered and sponsored by SilverScript© Insurance Company.
As a proud member of the CVS Health family of companies, SilverScript (PDP) shares that commitment by offering affordable, high quality coverage to people with Medicare. Unlike other Medicare insurers, Part D prescription drug coverage is our only business and has been since the Part D program began. We have the experience, expertise and focus to deliver high quality, affordable coverage that millions1 of Americans from all walks of life count on everyday for peace of mind.
Each year, Medicare Part D requires group health plan sponsors to disclose to individuals who are eligible for Medicare Part D and to the Centers for Medicare and Medicaid Services (CMS) whether the health plan’s prescription drug coverage is creditable. Plan sponsors must provide the annual disclosure notice to Medicare-eligible individuals before Oct. 15, 2016-the start date of the annual enrollment period for Medicare Part D. CMS has provided model disclosure notices for employers to use.