"If the intern does not complete your plan's waiting period, you would not have to report them because an individual is not considered a 'full-time employee' when in a limited non-assessment period (which is a fancy term for a waiting period that is 90 days or less). If the intern works past the waiting period, you will need to report the intern if the intern was working a full-time schedule. If the intern does not receive an offer of coverage, you have to report it as such and risk incurring a penalty under the ACA if the intern receives a subsidy from an Exchange plan during that month."