In the case of an employer to whom an election under this section applies for any calendar year, there is hereby imposed a tax for such calendar year equal to 30 percent of the excess fringe benefits.
An election under this section shall apply to the calendar year for which made and all subsequent calendar years unless revoked by the employer.
All employees treated as employed by a single employer under subsection (b), (c), or (m) of section 414 shall be treated as employed by a single employer for purposes of this section.
Except as otherwise provided in regulations, this section shall apply only with respect to employment within the United States.