What Is a Net Operating Loss?
An NOL is a tax concept, not a GAAP one: it measures the excess of allowable deductions over gross income on a company's tax return. Rather than letting that loss go to waste, the tax code allows the company to carry it forward and apply it against future taxable income, reducing cash taxes in profitable years. On the GAAP balance sheet, the expected benefit appears as a deferred tax asset.
The 2017 Tax Cuts and Jobs Act reshaped the federal rules. Losses generated in 2018 and later can be carried forward indefinitely but can offset only 80% of a year's taxable income, and carrybacks were generally eliminated outside of a temporary CARES Act window for pandemic-era losses. Older pre-2018 NOLs kept their original terms, including a 20-year carryforward life and 100% usability.
How NOLs Are Used and Valued
Suppose a company loses $50 million in its early years, then earns $30 million of taxable income the following year. The 80% limitation caps the NOL usage at $24 million, so the company pays federal tax on $6 million and carries the remaining $26 million of losses forward. At a 21% federal rate, the full NOL pool represents up to $10.5 million of future cash tax savings, worth less in present-value terms the longer it takes to use.
A critical constraint is Section 382 of the tax code. When a company undergoes an ownership change — broadly, a shift of more than 50 percentage points among large shareholders over three years — annual NOL usage is capped at roughly the company's equity value multiplied by a published long-term tax-exempt rate. This prevents profitable acquirers from buying shell companies purely to harvest their losses.
Why NOLs Matter in Deals and Models
NOLs show up constantly in M&A and restructuring work. Buyers model the present value of a target's usable NOLs as a discrete source of value, taking Section 382 limits into account, and distressed investors pay close attention to preserving NOLs through Chapter 11 because a reorganized company's losses can shelter years of future earnings. Some bankruptcy plans are structured specifically around keeping them intact.
In modeling, an NOL schedule tracks the beginning balance, losses generated, losses used against pre-tax income, and the ending balance, feeding the difference between book and cash taxes. A frequent interview prompt asks how a money-losing startup can be attractive to a profitable acquirer; discussing NOL carryforwards, alongside strategic rationale, is part of a complete answer.
