Short answer: Federal rules let an employer offer an Individual Coverage HRA (ICHRA) to specific, defined classes of employees rather than everyone, and the employer must apply the same terms to all employees in a class. The permitted classes include full-time, part-time, salaried, hourly, seasonal, those in the same insurance rating area, new hires, and a few others.
An ICHRA does not have to be offered to the whole workforce. The regulations let an employer divide employees into set classes and offer the ICHRA, or a different benefit, to each. Recognized classes include full-time and part-time employees, employees paid on a salary basis, non-salaried (hourly) employees, seasonal employees, and, for example, employees whose primary site of employment is in the same rating area.
The classes cannot be drawn arbitrarily; they are limited to the categories in the rule, and the employer must apply the same terms to all employees in a class (though the dollar amount may vary by age and family size). To keep employers from steering sicker workers off the group plan, the rules also set a minimum class size when a traditional group plan is offered to one class and an ICHRA to another. An employee offered an affordable ICHRA generally cannot also claim a premium tax credit.