This question is answered by the IRS: https://www.irs.gov/affordable-care-act/employers/questions-and-answers-on-employer-shared-responsibility-provisions-under-the-affordable-care-act
The general procedures the IRS will use to propose and assess the employer shared responsibility payment are described in Letter 226J. The IRS plans to issue Letter 226J to an ALE if it determines that, for at least one month in the year, one or more of the ALE’s full-time employees was enrolled in a qualified health plan for which a premium tax credit was allowed (and the ALE did not qualify for an affordability safe harbor or other relief for the employee).
Letter 226J will include: ua brief explanation of section 4980H, uan employer shared responsibility payment summary table itemizing the proposed payment by month and indicating for each month if the liability is under section 4980H(a) or section 4980H(b) or neither, uan explanation of the employer shared responsibility payment summary table, uan employer shared responsibility response form, Form 14764, “ESRP Response”, uan employee PTC list, Form 14765, “Employee Premium Tax Credit (PTC) List”which lists, by month, the ALE’s assessable full-time employees (individuals who for at least one month in the year were full-time employees allowed a premium tax credit and for whom the ALE did not qualify for an affordability safe harbor or other relief (see instructions for Forms 1094-C and 1095-C, Line 16), and the indicator codes, if any, the ALE reported on lines 14 and 16 of each assessable full-time employee’s Form 1095-C, ua description of the actions the ALE should take if it agrees or disagrees with the proposed employer shared responsibility payment in Letter 226J, and ua description of the actions the IRS will take if the ALE does not respond timely to Letter 226J.
The response to Letter 226J will be due by the response date shown on Letter 226J, which generally will be 30 days from the date of Letter 226J.
Letter 226J will contain the name and contact information of a specific IRS employee that the ALE should contact if the ALE has questions about the letter.