The Internal Revenue Service issued a set of proposed regulations Thursday on the base erosion and anti-abuse tax, or BEAT, for multinational companies that was included in the Tax Cuts and Jobs Act.

Last December’s tax overhaul added section 59A to the tax code, but the hastily written provisions have perplexed many tax practitioners and spurred demand for further guidance from the IRS on how the new BEAT provisions will affect the U.S. international tax system in the future. The proposed regulations aim to address some of those questions. Among other changes made by the new tax law, the new section 59A imposes a tax equal to the base erosion minimum tax amount for certain taxpayers starting in tax year 2018. When applicable, that tax comes in addition to the taxpayer’s regular tax liability. The new provision will mainoly affect corporate taxpayers whose gross receipts average more than $500 million over a three-year period who make deductible payments to foreign related parties.

The proposed regulations include detailed guidance about which taxpayers will be subject to the section 59A rules, the determination of what is a base erosion payment, the method for calculating the base erosion minimum tax amount, and the required base erosion and anti-abuse tax resulting from that calculation.

The Treasury Department and the IRS are asking for public comments on the proposed regulations, which include details about how to submit comments.