"To determine whether the tax applies, the employer will look to each covered employee and determine the total cost of coverage ... [then] notify each coverage provider of the proportionate amount of tax owed by that provider. Then, the provider will remit payment to the IRS (and will likely charge that cost back to the employer).... For insured coverage, the coverage provider is the insurer. For HSAs, the employer is the coverage provider. In all other instances, the coverage provider is the 'person who administers the coverage.' Does that mean the TPA [in a detailed example] owes the $157 to the IRS? Or should ABC, the plan sponsor, be liable?"