At this point, most employers understand the basics of the Affordable Care Act (ACA) but they may still have questions about many of its details. The IRS recently issued a series of Q&As to help answer some specifics around the Act.

Here are selected questions from the IRS, along with answers that are edited for space limitations:

Q. What are the Employer Shared Responsibility provisions? When do they go into effect?

For 2015 and later, employers with at least a certain number of employees (generally 50 full-time or a combination of full-time and part-time employees that is equivalent to 50 full-timers) will be subject to the Employer Shared Responsibility provisions under section 4980H of the Internal Revenue Code. (This is sometimes called “the employer mandate.”)

As defined by the statute, a full-time employee is employed on average at least 30 hours per week.

An employer that meets the 50 full-time employee threshold is referred to as an applicable large employer. If these employers don’t offer affordable health insurance that provides a minimum level of coverage to their full-timers (and their dependents), the employer may be subject to an Employer Shared Responsibility payment if at least one of its full-time employees receives a premium tax credit for purchasing individual coverage on one of the new Affordable Insurance Exchanges, also called the Health Insurance Marketplace.

The Shared Responsibility provisions aren’t effective until January 1, 2015, meaning no payments will be assessed for 2014. Employers will use information about the number of employees they employ and their hours during 2014 to determine whether they’re considered an applicable large employer for 2015.

Q. How many employees must an employer have to be subject to the Shared Responsibility provisions?

To be subject to the provisions for a calendar year, an employer must have employed during the previous calendar year at least 50 full-time employees or a combination of full-time and part-time employees that equals at least 50. For example, an employer that employs 40 full-time employees (that is, employees employed 30 or more hours a week on average) and 20 employees employed 15 hours a week on average has the equivalent of 50 full-time employees, and would be an applicable large employer.

Seasonal workers are taken into account in determining the number of full-time employees. However, if an employer’s workforce exceeds 50 full-time employees (including full-time equivalents or FTEs) for 120 days or fewer during a calendar year, and the employees in excess of 50 who were employed during that period of no more than 120 days were seasonal workers, the employer is not considered an applicable large employer.

Seasonal workers are those who perform labor or services on a seasonal basis as defined by the Secretary of Labor, and retail workers employed exclusively during holiday seasons. For this purpose, employers may apply a reasonable, good faith interpretation of “seasonal worker.”

Employers will determine each year based on their current number of employees whether they’ll be considered an applicable large employer for the next year. For example, if an employer has at least 50 full-time employees (including FTEs) for 2014, it will be considered a large employer for 2015.

Note: Since employers will be performing this calculation for the first time to determine their status for 2015, there is a transition rule intended to make this first calculation easier.

Employers average their number of employees across the months in the year to see whether they’ll be an applicable large employer for the next year. This can take account of fluctuations that many employers experience. The final regulations provide additional information about how to determine the average number of employees for a year, including how to take account of salaried employees who may not clock their hours.

Q. How does an employer not in existence the preceding calendar year determine if it has enough employees to be subject to the Shared Responsibility provisions?

An employer not in existence on any business day in the prior calendar year is considered an applicable large employer in the current year if the employer is reasonably expected to employ an average of at least 50 full-time employees (including full-time equivalents) on business days during the current calendar year and it actually employs an average of at least 50 full-time employees (including FTEs) on business days during the calendar year.

In contrast, for the next year (the year after the first year), the employer will determine its status as an applicable large employer using the rules that generally apply (that is, based on the number of full-time employees and full-time equivalents that the employer employed the preceding year).

Q. If two or more companies have a common owner or are otherwise related, are they combined for purposes of determining whether they employ enough employees to be subject to the Shared Responsibility provisions?

Yes, Section 4980H includes a longstanding provision that also applies for other tax and employee benefit purposes. Under it, companies with a common owner or that are otherwise related generally are combined and treated as a single employer. So they would be combined for purposes of determining whether or not they collectively employ at least 50 full-time employees (including FTEs). If the combined total meets the threshold, then each separate company is subject to the Sh