Net Operating Loss (NOL): Definition and How It Works

A Net Operating Loss (NOL) occurs when a taxpayer's allowable deductions exceed gross income for the tax year. Under IRC §172, a business or individual that generates an NOL may carry that loss forward to offset future taxable income, reducing tax liability in profitable years. NOLs are a critical planning tool for businesses with cyclical income, startup losses, casualty events, or unusual capital expenditures, and they are central to year-end tax projections and multi-year planning strategies that CPAs execute for business clients.

How NOLs Arise

An NOL can be generated by a sole proprietor, C-Corporation, partnership, S-Corporation (at the shareholder level), or individual with significant business or rental losses. The calculation begins with taxable income and adds back specific items — nonbusiness deductions in excess of nonbusiness income, the net operating loss deduction itself, and certain capital loss deductions — to arrive at the NOL amount available for carryforward.

Common NOL-generating scenarios:

  • Startup losses: A new business with significant upfront costs (payroll, rent, equipment, marketing) before meaningful revenue
  • Natural disasters or casualty events: Large uninsured losses that exceed income in the event year
  • Economic downturns: Sustained revenue declines with fixed cost structures
  • Accelerated depreciation: Large bonus depreciation or Section 179 deductions that create a paper loss in a profitable business
  • Real estate losses: Net rental losses (for real estate professionals who qualify to deduct them against ordinary income)

Current NOL Rules (Post-TCJA and OBBBA)

The Tax Cuts and Jobs Act (2017) and subsequent legislation significantly changed NOL mechanics:

Carryforward: Indefinite. NOLs generated in tax years ending after December 31, 2017 carry forward indefinitely. There is no longer a 2-year carryback provision for most taxpayers (the general carryback was eliminated by TCJA). Exceptions apply: farming losses retain a 2-year carryback; non-life insurance companies follow different rules.

80% taxable income limitation: An NOL may only offset up to 80% of the taxpayer's taxable income in the carryforward year (IRC §172(a)(2)). This means taxpayers cannot fully eliminate taxable income using a carried-forward NOL — at least 20% of taxable income remains subject to tax in any year where the NOL is applied.

No carryback for most taxpayers: Unlike pre-TCJA rules, general business NOLs cannot be carried back to prior tax years (with limited exceptions noted above). The ability to carry back losses and obtain immediate refunds from prior-year taxes was eliminated for most entities.

Pre-2018 NOLs: NOLs generated before January 1, 2018 follow prior-law rules — they carry forward for 20 years and are not subject to the 80% limitation. For clients with old NOL carryforwards, these rules remain applicable.

Interaction with Excess Business Loss Limitation

The Excess Business Loss (EBL) limitation under IRC §461(l) — made permanent by the One Big Beautiful Bill Act — interacts directly with NOL planning. Under the EBL rule, non-corporate taxpayers (individuals, trusts) cannot deduct aggregate business losses exceeding $256,000 (single) or $512,000 (MFJ) for 2026. Losses in excess of these thresholds are not deductible in the current year; instead, they convert to NOL carryforwards subject to the 80% limitation. Understanding this interaction is essential for clients with large pass-through losses, rental losses, or farming losses. See Excess Business Loss Limitation for the full planning analysis.

NOL Tracking and Documentation

CPAs must maintain accurate NOL carryforward schedules, including:

  • The year(s) in which each NOL was generated
  • Whether the loss is subject to pre-2018 or post-2017 rules
  • The amount consumed each year and the remaining carryforward balance
  • For partnership and S-Corp clients: whether losses passed through to owners were limited by basis, at-risk, or passive activity rules before generating an NOL at the owner level

Inadequate NOL records are a common audit issue. The IRS may challenge stale carryforwards that lack documentation of their origin.

Related Terms

  • Excess Business Loss — the §461(l) annual cap on pass-through losses for non-corporate taxpayers; excess amounts convert to NOL carryforwards
  • Bonus Depreciation — one of the most common NOL-generating mechanisms for capital-intensive businesses, particularly when 100% expensing is available
  • Pass-Through Entity — NOLs from S-Corps and partnerships flow to owners' returns, where they are subject to basis, at-risk, and passive activity limitations before generating an individual-level NOL

How CPAs Use NOLs in Practice

NOL planning involves two related decisions: generation (when to accelerate deductions to create a larger loss) and utilization (managing income recognition to maximize the value of the carryforward). Because of the 80% limitation, a large NOL carryforward may take many years to fully utilize. CPAs use NOL schedules to model the present value of future tax savings, evaluate whether a Roth conversion makes sense in a high-loss year, and determine whether an asset sale should be timed to coincide with available NOL carryforwards. For comprehensive carryforward mechanics and planning scenarios, see the full guide at Net Operating Loss Carryforward Rules.