The US Internal Revenue Service has issued guidance on the Tax Cuts and Jobs Act 2017's limitations on business losses, which restrict the deductible losses from all types of business for non-corporate taxpayers. 

Disallowed excess business losses, defined as the amount by which the total deductions from all trades or businesses exceed a taxpayer's total gross income and gains from those trades or businesses, plus USD250,000, are now treated as a net operating loss (NOL) carryover to the following tax year. Also, taxpayers other than farmers and insurance companies no longer have the option to carryback a NOL, and NOLs arising in tax years ending after 2017 can only be carried forward.