One Big Beautiful Bill Act Explained: 100% Expensing, Section 179 & New 2025-2028 Tax Deductions

[Last Updated on 2 weeks ago]

The One Big Beautiful Bill Act, signed into law on July 4, 2025, as Public Law 119-21, made major changes to federal tax deductions, depreciation planning, and CPA compliance workflows. For tax professionals, the biggest practical shift is the return of 100% bonus depreciation for qualifying property, along with expanded Section 179 limits and new temporary deductions for certain workers, vehicle buyers, and seniors. (IRS)

This guide explains what changed, how CPAs should handle Form 4562 and client planning, and where firms need stronger documentation before filing.

For a deeper depreciation-specific workflow, see our guide to bonus depreciation planning for CPAs.

What is the One Big Beautiful Bill Act?

The One Big Beautiful Bill Act (OBBBA), codified as Public Law 119-21 and enacted through H.R. 1 (119th Congress, 2025-2026), restructures multiple tax chapters within the Internal Revenue Code.

• Chapter 1 – Depreciation Provisions: Permanently restores 100% bonus depreciation under IRC §168(k) for property placed in service after January 19, 2025.
• Chapter 2 – Expensing Coordination: Aligns §168(k) with the enhanced §179 expensing limits, allowing combined use for strategic capital planning.
• Chapter 3 – Qualified Property Definitions: Expands eligibility to machinery, vehicles, leasehold, and real estate improvements with ≤20-year recovery periods, including Qualified Improvement Property (QIP).
• Chapter 4 – Reporting and Compliance: Requires all bonus depreciation and expense claims to be filed using IRS Form 4562 for transparent documentation.
• Chapter 5 – Fiscal Policy Intent: Designed to stimulate capital formation, manufacturing growth, and small-business competitiveness by making full expensing permanent.

Lawmakers structured OBBBA to eliminate the Tax Cuts and Jobs Act (TCJA) phase-down schedule and simplify depreciation management for CPAs and firms. Together, these chapters modernize U.S. depreciation policy for long-term business investment.

Key OBBBA Tax Changes CPAs Should Know

Area	What changed	Effective period
Bonus depreciation	100% additional first-year depreciation for qualified property acquired after January 19, 2025	Permanent, subject to qualification rules
Section 179	Deduction limit increased to $2.5 million; phaseout threshold increased to $4 million	Tax years beginning after 2024
Qualified tips	Up to $25,000 deduction, subject to eligibility and MAGI phaseout	2025–2028
Qualified overtime	Up to $12,500 deduction, or $25,000 for joint filers	2025–2028
Car loan interest	Up to $10,000 deduction for qualifying personal-use vehicle loans	2025–2028
Senior deduction	Additional $6,000 deduction per eligible taxpayer age 65+	2025–2028
Clean vehicle credits	Several credits end for vehicles acquired after September 30, 2025	Phaseout rules vary
Home energy credits	Certain home energy credits end after December 31, 2025	Phaseout rules vary

Treasury and the IRS issued interim guidance stating that the OBBB provides a permanent 100% additional first-year depreciation deduction for qualified property acquired, or specified plants planted or grafted, after January 19, 2025. 

Why OBBBA Matters for CPA Firms

OBBBA is not just a tax-law update. It changes how CPA firms should collect client information, document fixed assets, model depreciation, and review individual deductions.

The most immediate CPA workflow changes are:

1. Updating fixed-asset intake for acquisition date, placed-in-service date, recovery period, asset location, and business-use percentage.
2. Rebuilding Form 4562 review procedures for Section 179, bonus depreciation, and elections.
3. Adding client organizer questions for tips, overtime, vehicle loans, and senior deduction eligibility.
4. Maintaining separate federal and state depreciation schedules where states decouple from federal bonus depreciation.
5. Reviewing clean energy and vehicle credit eligibility before assuming prior-year rules still apply.

CPA firms that already have a year-end research process should update it for OBBBA. If your team needs a research control framework, use this year-end tax research review process as a starting point.

Permanent 100% Bonus Depreciation Under OBBBA

OBBBA restores and makes permanent 100% bonus depreciation for qualifying property acquired after January 19, 2025. The rule generally applies to eligible depreciable property that meets the requirements under Section 168(k), including qualified property and certain specified plants. (IRS)

The IRS guidance also confirms that taxpayers may generally rely on existing additional first-year depreciation regulations while applying the updated OBBBA dates and percentages. (IRS)

Planning Checks Before Claiming Full Bonus Depreciation

Before claiming 100% bonus depreciation, confirm:

• The asset was acquired after January 19, 2025.
• The asset was placed in service during the tax year.
• The property qualifies under Section 168(k).
• Business-use percentage supports the deduction.
• Listed-property records are complete.
• The client understands state conformity differences.
• The deduction does not create an unwanted NOL, QBI limitation issue, basis limitation, passive loss issue, or lending covenant problem.

For many clients, the question is not simply, “Can we deduct it?” The better question is, “Should we deduct all of it this year?”

Section 179 Expensing After OBBBA

OBBBA also increased the Section 179 expensing limits. The law amended Section 179 by increasing the deduction cap from $1 million to $2.5 million and the phaseout threshold from $2.5 million to $4 million. (budget.senate.gov)

That creates more flexibility for small and mid-sized businesses, especially when CPAs want to choose a specific deduction amount rather than automatically apply full bonus depreciation.

Section 179 vs. Bonus Depreciation for Capital Planning

Section 179 and bonus depreciation can both accelerate deductions, but they are not interchangeable.

• Section 179 is elective and limited by taxable business income. It can be useful when the CPA wants to expense specific assets while controlling the deduction amount.

• Bonus depreciation generally applies more broadly to qualifying property and can create or increase a net operating loss. It may be more powerful, but it can also create timing problems if used without forecasting.

In most cases, CPAs should model Section 179 first, then apply bonus depreciation to the remaining qualifying basis when appropriate.

Qualified Production Property and Manufacturing Expensing

OBBBA also created a special depreciation opportunity for qualified production property. IRS guidance describes this as a rule that allows businesses to write off certain property more quickly, generally for qualifying business property bought and placed in use after January 19, 2025. 

This topic is especially important for manufacturers, producers, and businesses investing in machinery, equipment, facilities, or other qualifying production assets.

Eligibility Checks for Production Property Expensing

• Whether the property is used in a qualifying production activity.
• Whether original-use and placed-in-service requirements are met.
• Whether the property is used in the United States or a U.S. possession.
• Whether any portion of the property is excluded because it relates to offices, administrative services, lodging, parking, sales, software engineering, or other non-production functions.
• Whether recapture could apply if the property stops being used for qualified production.

This is an area where firms should avoid shortcut summaries. The facts matter.

How CPAs Should Report OBBBA Depreciation on Form 4562

Form 4562 reporting should start with documentation, not data entry.

A reliable OBBBA depreciation workpaper should show the asset description, acquisition date, placed-in-service date, cost, recovery period, business-use percentage, Section 179 election amount, bonus depreciation treatment, state adjustment, and reviewer conclusion.

Form 4562 Workpaper Checklist

1. Classify the asset. Identify whether the asset is machinery, equipment, qualified improvement property, listed property, vehicle, software, specified plant, or another qualifying class.
2. Confirm timing. Tie the acquisition date and placed-in-service date to invoices, contracts, delivery records, and client representations.
3. Apply Section 179 intentionally. Use it where the client benefits from a controlled elected deduction.
4. Model bonus depreciation. Compare current-year savings with multi-year tax outcomes.
5. Check elections. The IRS says taxpayers may elect 40% instead of 100% for qualified property placed in service during the first tax year ending after January 19, 2025, with a 60% rule for certain longer-production-period property and aircraft. 
6. Reconcile state treatment. Keep separate federal and state depreciation schedules when conformity differs.

CPA Pilot can help standardize this process by generating Form 4562 workpapers, asset summaries, election language, and client-ready explanations. For firms building broader automation around return preparation, see our guide to 1040 workflow automation for tax firms.

Example: Coordinating Section 179 and Bonus Depreciation

Assume a calendar-year S corporation buys and places in service $600,000 of qualifying five-year machinery in September 2025.

If the property meets Section 168(k) requirements and the taxpayer does not elect out, the business may be able to claim 100% bonus depreciation federally. But the CPA should still review:

• Whether Section 179 would produce a better controlled deduction.
• Whether shareholders have enough basis.
• Whether passive activity rules limit loss use.
• Whether the deduction affects QBI.
• Whether a state addback applies.
• Whether a full current-year deduction helps or hurts projected 2026 tax planning.

This kind of scenario should be documented before the return is finalized, not after a reviewer questions the deduction.

New Individual Deductions for 2025 Through 2028

OBBBA created several temporary deductions for individuals. These deductions are available for 2025 through 2028, but each has eligibility rules, documentation requirements, and income phaseouts. 

Qualified Tips Deduction

Employees and self-employed individuals may deduct up to $25,000 of qualified tips received in eligible occupations. The IRS says qualified tips must be voluntary cash or charged tips received from customers or through tip sharing, and they must be reported on Form W-2, Form 1099, another specified statement, or Form 4137. The deduction phases out when modified AGI exceeds $150,000, or $300,000 for joint filers. 

CPA intake should verify occupation, reported tip source, Social Security number, filing status, and whether SSTB restrictions apply.

Qualified Overtime Deduction

The overtime deduction applies only to the portion of qualified overtime compensation that exceeds the taxpayer’s regular rate of pay. For example, in a time-and-a-half arrangement, the deductible amount is generally the “half” portion, not the entire overtime wage. The maximum annual deduction is $12,500, or $25,000 for joint filers, with phaseouts beginning at $150,000 MAGI, or $300,000 for joint filers. (IRS)

CPA firms should be careful not to treat all overtime wages as deductible.

Car Loan Interest Deduction for Personal-Use Vehicles

The car loan interest deduction is for qualifying personal-use vehicles, not business or commercial-use vehicles. Individuals may deduct up to $10,000 of interest on a loan used to purchase a qualified vehicle, subject to a phaseout above $100,000 modified AGI, or $200,000 for joint filers. (IRS)

The loan must originate after December 31, 2024, the vehicle must be new, the vehicle must be secured by a lien, and the vehicle must have final assembly in the United States. The taxpayer must include the VIN on the return for any year the deduction is claimed. (IRS)

Additional Senior Deduction for Taxpayers Age 65 and Older

Taxpayers age 65 or older may claim an additional $6,000 deduction for 2025 through 2028. This is in addition to the existing senior standard deduction. The $6,000 amount applies per eligible individual, so a married couple may qualify for up to $12,000 if both spouses meet the age requirement. The deduction phases out above $75,000 modified AGI, or $150,000 for joint filers. 

This is a deduction, not a refundable credit.

Clean Energy and Vehicle Credit Phaseouts

OBBBA also accelerated the end of several clean energy and vehicle credits.

The IRS says the New Clean Vehicle Credit, Used Clean Vehicle Credit, and Qualified Commercial Clean Vehicle Credit are not allowed for vehicles acquired after September 30, 2025. 

For home energy credits, the IRS says the Energy Efficient Home Improvement Credit is not allowed for property placed in service after December 31, 2025, and the Residential Clean Energy Credit is not allowed for expenditures made after December 31, 2025. (IRS)

CPAs should update client-facing planning memos so taxpayers do not assume 2024 or early-2025 credit rules still apply.

State Conformity Risks for Bonus Depreciation

Federal 100% spending does not guarantee the same state result.

Some states conform automatically to federal depreciation rules. Others decouple, require addbacks, or apply their own depreciation schedules. For multi-state clients, CPAs should create a federal-state depreciation reconciliation before filing.

At minimum, retain:

• Federal depreciation schedule.
• State-adjusted depreciation schedule.
• State addback calculation.
• Workpaper showing conformity position.
• Reviewer signoff for high-dollar assets.
• Client explanation for timing differences.

For firms using AI in research, the safest workflow is authority-first: start with IRS, state revenue department guidance, statutes, and forms before relying on summaries. Our article onAI tax research workflows explains how to build that process without losing source control.

CPA Firm Checklist for OBBBA Compliance

Before filing 2025 or 2026 returns affected by OBBBA, review these areas:

• Fixed-asset intake includes acquisition date and placed-in-service date.
• Form 4562 workpapers distinguish Section 179, bonus depreciation, and state adjustments.
• OBBBA elections are documented before filing.
• Business-use percentages are supported for vehicles and listed property.
• Individual organizers ask about tips, overtime, vehicle loans, VINs, senior age eligibility, and MAGI.
• State conformity has been checked for every material depreciation deduction.
• Clean energy credits are reviewed against the new expiration dates.
• Client memos explain assumptions, limitations, and documentation requirements.

This checklist should become part of the firm’s standard 2025 return-preparation workflow.

Where CPA Pilot Fits Into the OBBBA Workflow

OBBBA creates a documentation challenge for tax firms: more deductions, more eligibility rules, more client questions, and more review points.

CPA Pilot is built for CPAs, EAs, and tax firms that need citation-backed answers, tax research support, client-ready deliverables, and workflow automation. Use CPA Pilot to:

• Generate depreciation workpapers.
• Draft client explanations for OBBBA changes.
• Compare Section 179 and bonus depreciation outcomes.
• Create research memos with IRS and state citations.
• Standardize reviewer checklists.
• Draft client emails for new deduction eligibility.

Ready to turn OBBBA research into audit-ready workpapers? Book a CPA Pilot demo and see how your firm can move from tax-law updates to finished client deliverables faster.

OBBBA FAQs for CPAs

Is 100% Bonus Depreciation Permanent Under OBBBA?

Yes. Treasury and IRS guidance describes the OBBB as providing a permanent 100% additional first-year depreciation deduction for qualified property acquired, or specified plants planted or grafted, after January 19, 2025. 

Should CPAs Claim Full Bonus Depreciation Automatically?

No. Full expensing may not be best when it creates an unwanted NOL, reduces QBI benefits, creates state addbacks, affects owner basis, triggers passive loss limitations, or causes financial statement or loan covenant issues.

How Did OBBBA Change Section 179?

OBBBA increased the Section 179 deduction limit to $2.5 million and the phaseout threshold to $4 million for property placed in service in tax years beginning after 2024. (Center for Agricultural Law and Taxation)

Does the Car Loan Interest Deduction Apply to Business Vehicles?

No. IRS guidance says the vehicle must be purchased for personal use, not business or commercial use. Lease payments do not qualify. 

Is the Senior Tax Benefit a Refundable Credit?

No. The senior benefit is an additional deduction of $6,000 per eligible taxpayer age 65 or older, subject to income phaseout. 

What Is the Biggest CPA Risk Under OBBBA?

The biggest risk is overclaiming deductions without documenting eligibility. Bonus depreciation, Section 179, vehicle interest, tips, overtime, and senior deductions all require fact-specific review.

High Authority References Used

• IRS — One Big Beautiful Bill provisions
  https://www.irs.gov/newsroom/one-big-beautiful-bill-provisions 
• IRS — Treasury and IRS guidance on additional first-year depreciation under OBBBA
  https://www.irs.gov/newsroom/treasury-irs-issue-guidance-on-the-additional-first-year-depreciation-deduction-amended-as-part-of-the-one-big-beautiful-bill 
• IRS — OBBBA tax deductions for working Americans and seniors
  https://www.irs.gov/newsroom/one-big-beautiful-bill-act-tax-deductions-for-working-americans-and-seniors 
• U.S. Senate Budget Committee — One Big Beautiful Bill Act PDF
  https://www.budget.senate.gov/imo/media/doc/the_one_big_beautiful_bill_act.pdf 
• Center for Agricultural Law and Taxation — OBBBA tax package summary
  https://www.calt.iastate.edu/post/one-big-beautiful-bill-act-implements-significant-tax-package 
• IRS — One Big Beautiful Bill provisions
  https://www.irs.gov/newsroom/one-big-beautiful-bill-provisions 
• GovInfo — Public Law 119-21
  https://www.govinfo.gov/link/plaw/119/public/21 
• IRS — 2025 Instructions for Form 4562
  https://www.irs.gov/instructions/i4562