6. Detailed rules. There are various detailed rules that fall within the responsibility of the employer that include items such as: (1) holding employer contributions for an employee who  fails to open an HSA; (2) not being able to "recoup" money mistakenly made to an employee's HSA; (3) actually making employer HSA contributions into employees HSAs on a timely basis, and (4) other detailed rules.

Here are 6 HSA responsibilities of employers if they offer pre-tax employer contributions. (All photos: Shutterstock)

1. Make comparable contributions. If the employer is making a pretax employer contribution (non-payroll deferral), it must do so on a comparable basis.

2. Maintain Section 125 plan for payroll deferral. If the employer allows pre-tax payroll deferral, then the employer must adopt and maintain a Section 125 plan that provides for HSA deferrals. This includes collecting employee deferral elections, sending the deferred amount directly to the HSA custodian, and accounting for the money for tax-reporting purposes.

3. Work with employees on HSA eligibility and contribution limits. Employers should work with employees to determine eligibility for an HSA and the employee's HSA contribution limit. Although it is legally the employee's responsibility to determine his or her eligibility and contribution limit, a mistake in these areas generally involves work by both the employer and the employee to correct.

Also, the employer does have some responsibility not to exceed the known federal limits. An employer may not know if a particular employee is ineligible for an HSA due to other health coverage but an employer is expected to know the current HSA limits for the year and not exceed those limits.

4. Tax reporting. The employer needs to properly complete employees' W-2 forms and its own tax-filing regarding HSAs (HSA employer contributions are generally deductible as a benefit under IRC Section 106).

5. Business owner rules. Business owners generally are not treated as employees and employers need to review HSA contributions for business owners for proper tax reporting.

6. Detailed rules. There are various detailed rules that fall within the responsibility of the employer that include items such as: (1) holding employer contributions for an employee who  fails to open an HSA; (2) not being able to "recoup" money mistakenly made to an employee's HSA; (3) actually making employer HSA contributions into employees HSAs on a timely basis, and (4) other detailed rules.