Section 179 expensing and bonus depreciation: how business equipment expensing actually works after TCJA

The combination of IRC §179 immediate expensing and IRC §168(k) bonus depreciation provides one of the most powerful tax-deferral tools available to small and mid-size businesses for capital equipment acquisition. The two provisions operate together but with different rules, limitations, and phase-out schedules. The 2017 Tax Cuts and Jobs Act (TCJA) expanded both provisions, but bonus depreciation is currently scheduled to sunset under the original TCJA phase-down schedule (100% bonus through 2022, 80% in 2023, 60% in 2024, 40% in 2025, 20% in 2026, and 0% from 2027 forward, absent legislative action to extend).

The substantive effect of these provisions is to convert what would otherwise be multi-year depreciation deductions into immediate first-year deductions. A business purchasing $500,000 of qualifying equipment under normal Modified Accelerated Cost Recovery System (MACRS) depreciation would deduct $500,000 spread over 5-7 years (depending on equipment classification). Under §179 or bonus depreciation, the same $500,000 can be deducted in the first year, reducing current-year taxable income and creating tax-deferral benefits. For a business in the 37% tax bracket, the first-year deduction creates approximately $185,000 of immediate tax savings on the $500,000 purchase, compared to spreading the same tax benefit over 5-7 years under normal depreciation.

• Use qualifying property (most business equipment qualifies; some real property qualifies for §179 only)
• Place property in service during tax year (delivery alone insufficient)
• Use property predominantly in trade or business (>50% business use minimum)
• Make timely §179 election on the tax return
• Stay within annual dollar limits
• Address phase-out thresholds based on total qualifying purchases
• Comply with various recapture provisions

This is how the §179 and bonus depreciation framework actually works post-TCJA, the requirements for each provision, the strategic interaction between §179 and bonus depreciation, the phase-down schedule and planning considerations, and the strategic considerations for business owners using equipment expensing.

What does Section 179 actually do?

Section 179 of the Internal Revenue Code allows businesses to elect to deduct the full cost of qualifying equipment in the year it is placed in service, rather than depreciating it over multiple years. For 2024, the maximum deduction is $1,160,000, with a phase-out beginning at $2,890,000 in total qualifying purchases. The deduction cannot exceed the business's taxable income.

Under IRC §179(a):

"A taxpayer may elect to treat the cost of any section 179 property as an expense which is not chargeable to capital account. Any cost so treated shall be allowed as a deduction for the taxable year in which the section 179 property is placed in service."

• Elect to deduct qualifying property cost in year placed in service

• Convert capital asset into immediate expense

• Avoid multi-year MACRS depreciation

• Maintain election year by year (flexibility)

• Maximum §179 deduction: $1,160,000

• Phase-out threshold: $2,890,000 of qualifying purchases

• Above threshold: §179 deduction reduced dollar-for-dollar

• Complete phase-out at $4,050,000 of qualifying purchases

• Maximum deduction: $1,220,000 (estimated, pending IRS adjustment)

• Phase-out threshold: $3,050,000 (estimated)

Indexing. Per IRC §179(b):

• Annual cost-of-living adjustments
• IRS Revenue Procedure updates each year

Taxable income limitation. Per IRC §179(b)(3):

• §179 deduction cannot exceed aggregate trade or business taxable income

• Disallowed amount carries forward indefinitely

• Limitation for small businesses with limited income

• Business buys $1,500,000 of equipment in 2024

• §179 elected on $1,160,000 (maximum)

• $1,500,000 - $1,160,000 = $340,000 (remaining basis)

• $340,000 available for bonus depreciation or MACRS

• 2024 bonus depreciation at 60%: $204,000 additional first-year

• Total first-year deduction: $1,364,000

• Remaining $136,000 depreciated under MACRS over 5-7 years

What property qualifies for Section 179 expensing?

Section 179 qualifying property includes most tangible business equipment (machinery, office equipment, furniture, manufacturing and construction equipment), off-the-shelf computer software, and certain real property improvements such as qualified improvement property, roofs, HVAC, and fire protection systems. Vehicles qualify with specific dollar limitations based on weight class.

Per IRC §179(d) and Treas. Reg. §1.179-4:

• Qualified Improvement Property (QIP): interior improvements to nonresidential property

• Heating, ventilation, air conditioning (HVAC)

• Fire protection and alarm systems

• Cars: Limited under "luxury auto" rules ($20,200 max in 2024 with bonus, $12,200 without)

• Light trucks/SUVs >6,000 lbs gross weight: Substantially higher limits

• Trucks >14,000 lbs: Full §179 available (no luxury auto limit)

• Cargo vans: Generally full §179 available

SUV exception. SUVs between 6,000 and 14,000 lbs gross vehicle weight:

• $30,500 §179 maximum (2024)

• Limited compared to other property

• Real property (buildings, structures) except as noted above

• Property used predominantly outside U.S.

• Property used for lodging (some exceptions)

• Property received from related persons

• Property used in a passive activity

What does bonus depreciation do?

Bonus depreciation under IRC §168(k) provides an additional first-year depreciation deduction for qualifying business property. Unlike Section 179, it has no dollar limit and no taxable income limitation. The TCJA set 100% bonus depreciation through 2022, now phasing down: 60% in 2024, 40% in 2025, 20% in 2026, and 0% from 2027, absent legislative action.

Under IRC §168(k):

Additional first-year depreciation deduction. Bonus depreciation provides:

• Percentage of qualifying property cost deductible in first year

• In addition to regular MACRS depreciation

• Different from §179 (which is immediate expensing election)

• 2017 (post-TCJA enactment) - 2022: 100%

• 2027 and later: 0% (under current law)

Note: Various bills propose extending or restoring bonus depreciation. Monitor tax legislation for changes.

What property qualifies for bonus depreciation?

Bonus depreciation applies to MACRS property with a recovery period of 20 years or less, including most tangible business equipment, computer software, and qualified improvement property. Post-TCJA, used property qualifies if it is the taxpayer's first use. Property used for residential rental or with recovery periods exceeding 20 years is excluded.

Per IRC §168(k)(2):

MACRS property with recovery period 20 years or less. Substantially:

Used property (TCJA expansion). Critical change from prior law:

• Pre-TCJA: Only new property qualified for bonus

• Post-TCJA: Used property qualifies if first use by taxpayer

• Planning opportunity for businesses buying used equipment

• Property used for residential rental

• Property with longer than 20-year recovery period

• Property required to use Alternative Depreciation System (ADS)

• Property used in trade or business of furnishing or sale of regulated utilities

• Pre-CARES Act: Mistakenly excluded from 100% bonus due to drafting error

• CARES Act (2020): Retroactively fixed to include QIP at 15-year recovery

• Current treatment: 15-year recovery, eligible for bonus depreciation

What are the differences between Section 179 and bonus depreciation?

Section 179 is an elective deduction with a $1,160,000 annual cap (2024) and a taxable income limitation, while bonus depreciation applies automatically with no dollar cap and can generate a net operating loss. Section 179 allows property-by-property elections; bonus depreciation applies by asset class and is phasing down to 0% by 2027.

Income tax planning differences

How do states treat Section 179 and bonus depreciation?

State conformity with federal Section 179 and bonus depreciation varies significantly. Some states fully conform to federal rules, others partially decouple (often rejecting bonus depreciation while allowing Section 179), and a few states reject both. California, New York, New Jersey, and Pennsylvania are among the states that have decoupled from federal bonus depreciation in part or in full.

Full federal conformity states. Most states follow federal §179 and bonus depreciation:

• Same federal limits and rules apply for state tax

• State tax savings combined with federal

• Decoupled from federal bonus depreciation

• May have own §179-equivalent provision

• Require adjustment to federal taxable income

• Don't allow bonus depreciation

• Require add-back of federal bonus on state return

• California: Decoupled from federal bonus depreciation; has own §179-equivalent

• New York: Decoupled in part

• New Jersey: Decoupled in part

• Various other states with specific rules

When do Section 179 and bonus depreciation recapture rules apply?

Recapture applies when Section 179 or bonus depreciation property is sold, exchanged, or converted to non-business use. Under IRC §1245, gain on sale is recaptured as ordinary income up to the total depreciation claimed. For Section 179 property, business use dropping below 50% during the recovery period also triggers recapture.

Under IRC §1245:

Sale or exchange of §1245 property. Triggers recapture:

• Sale price - adjusted basis = gain
• Gain up to depreciation deductions = ordinary income (recapture)
• Excess gain = capital gain (rare for fully depreciated property)

§179 recapture for business use changes

Reg. §1.179-1(e)](https://www.law.cornell.edu/cfr/text/26/1.179-1):

• Property must remain >50% business use

• Drop below 50% during recovery period triggers recapture

• Recapture amount = §179 deduction less depreciation allowed if no §179 election

• Personal use of business vehicle increasing

• Reduced business activity making property unused

• Trap for changing business circumstances

Under IRC §280F:

• Property generally used for entertainment, recreation, amusement
• Computers and peripherals (some exceptions)

How do Section 179 and bonus depreciation apply to vehicles?

Passenger automobiles face "luxury auto" limits under IRC §280F, capping the 2024 first-year deduction at $20,200 with bonus depreciation or $12,200 without. Heavy SUVs (6,000 to 14,000 lbs GVW) allow up to $30,500 in Section 179. Trucks exceeding 14,000 lbs GVW and cargo vans face no luxury auto limit, allowing full Section 179 expensing.

limitations. "Luxury auto" rules under IRC §280F:

• 2024 first-year limit: $20,200 (with bonus) or $12,200 (without bonus)
• Lower limits for subsequent years
• Constraints on luxury vehicle deductions

Reduces incentive for high-end passenger automobiles as business deductions.

Heavy SUVs (6,000-14,000 lbs GVW)

• $30,500 §179 maximum (2024)
• Substantially higher than passenger autos

What are the best strategies for using Section 179 and bonus depreciation?

Businesses should generally apply Section 179 first (up to the annual limit), then use bonus depreciation on remaining cost basis. Key strategies include timing purchases before year-end, monitoring the bonus depreciation phase-down schedule, tracking business use for vehicles and listed property, coordinating with state tax rules, and engaging a qualified tax professional for equipment acquisitions.

For business owners using §179 and bonus depreciation:

• December purchases (before year-end) qualify for current year
• "Placed in service" required (not just purchased)
• Equipment in business and ready for use

Use §179 before bonus depreciation typically. Strategic ordering:

• Cannot create loss with §179
• Planning for limited-income years
• May prefer bonus depreciation when §179 limitation would apply

Coordinate with pass-through entity choice:

• Different entities have different §179 considerations
• S-corp and partnership pass-through to owners
• Owner-level taxable income limitation
• Complexity for multi-owner entities

Watch the §179 phase-out threshold. $2,890,000 (2024):

• Large purchases reduce §179 amount
• Pure dollar-for-dollar reduction
• Bonus depreciation more useful at higher purchase levels

Address the §199A QBI deduction interaction:

Plan for SE tax mechanics:

Coordinate with reasonable compensation analysis:

• S-corp owners face reasonable compensation requirements

• Depreciation doesn't reduce reasonable compensation

• Maintain contemporaneous mileage logs (for vehicles)

• Listed property rules require strict compliance

Watch the §1031 like-kind exchange coordination:

• Post-TCJA, §1031 limited to real estate

• Equipment exchanges produce immediate gain

• §1245 recapture applies to equipment sales

• With §1031 elimination for personal property

• Interior improvements to nonresidential property

• 15-year recovery (post-CARES Act)

• $30,500 SUV maximum (2024)

• Luxury auto rules for passenger vehicles

• Heavy truck full deduction available

Engage qualified tax professional for purchases. purchases warrant:

Plan for end-of-year purchases. December often substantial:

• Equipment "placed in service" by December 31 qualifies for current year
• Documentation of placed-in-service date

Watch for accelerated depreciation legislation. Various bills proposed:

Address LLC operating agreement considerations:

Plan for Solo 401(k) and retirement contributions:

Address tax debt planning coordination:

• §179 deductions reduce current year tax

• May affect IRS installment agreement calculations

• Required for taxpayers with existing debt

• §1245 recapture on equipment sale

• §1031 limited to real estate

• Equipment held to depreciation completion ideal

Coordinate with phantom equity and profits interests:

Address the business succession planning integration:

For business owners with equipment purchase activity, the combination of §179 immediate expensing and §168(k) bonus depreciation provides tax-deferral opportunities that can materially affect annual tax liability. The combined effect can convert substantial portions of capital expenditures from multi-year depreciation deductions into immediate first-year deductions, creating current-year tax savings, particularly valuable for businesses in high tax brackets and businesses with equipment investment cycles. The framework's complexity (§179 limits, bonus depreciation phase-down schedule, vehicle limitations, listed property rules, state conformity issues, recapture provisions) means that careful planning, qualified professional engagement, and strategic timing of equipment purchases can substantially affect long-term tax outcomes. The work for business owners is in engaging qualified tax counsel early in equipment acquisition planning, coordinating §179 elections with bonus depreciation strategy, tracking business use carefully for vehicles and listed property, watching state tax conformity issues, planning around the bonus depreciation phase-down schedule (currently scheduled to sunset by 2027), and addressing coordination with other tax planning provisions including §1031, QBI, and retirement contributions. For appropriate business owners, the framework provides substantial tax savings that justify careful planning investment, and the current phase-down schedule creates near-term planning urgency that should drive equipment acquisition timing decisions during the transitional period.