Net Operating Losses  

A net operating loss (NOL) results from the situation in which a business or individual has more allowable tax deductions than it has taxable income. In this case, the business has negative income or a net operating loss. 

Before 2018, a taxpayer could take the net operating loss and move it back to a tax year in which they had a profit (actually, net operating income) either prior years or future years. 

Most taxpayers no longer have the option to carry back a net operating loss. For most taxpayers, NOLs arising in tax years ending after December 31, 2017, can only be carried forward. The 2-year carryback rule in effect before 2018, generally, does not apply to NOLs arising in tax years ending after December 31, 2017. Exceptions apply to certain farming losses and NOLs of insurance companies other than life insurance companies. For losses arising in taxable years beginning after Dec. 31, 2017, the new law limits the net operating loss deduction to 80% of taxable income (determined without regard to the NOL deduction).

NOLs are complicated and I recommend reading the IRS publication that provides extensive discussion and worksheets to assist in determining if (a) you have an NOL , and (b) the amount of the NOL that you can carry forward.

Publication 536 (2018), Net Operating Losses (NOLs) for Individuals, Estates, and Trusts