From the IRS [PDF]:
Section 4980I of the Tax Code, which was added by the Affordable Care Act and applies to taxable years beginning after Dec. 31, 2017. Under this provision, if the aggregate cost of “applicable employer-sponsored coverage” provided to an employee exceeds a statutory dollar limit, which is revised annually, the excess is subject to a 40 percent excise tax.
The notice describes potential approaches with regard to a number of issues under Section 4980I, which could be incorporated in future proposed regulations, and invites comments on these potential approaches.
The excise tax would take hold in 2018 and impose a 40% tax on employers for offering health benefits too generous they’ve been deemed a waste of healthcare spending dollars.