Example. During the 2007 calendar year, Employer D has 8 employees who are eligible individuals with self-only coverage under an HDHP provided by Employer D. The deductible for the HDHP is $2,000. For the 2007 calendar year, Employer D contributes $2,000 each to the HSAs of two employees and $1,000 each to the HSAs of the other six employees, for total HSA contributions of $10,000. Employer D's contributions do not satisfy the comparability rules. Therefore, Employer D is subject to an excise tax of $3,500 (35% of $10,000) for its failure to make comparable contributions to its employees' HSAs.
26 C.F.R. §54.4980G-1