Autonomous Taxation 2025: Complete Guide and Tax Optimisation Strategies

Autonomous Taxation (AT) in Portugal is a topic of extreme relevance for companies and self-employed individuals with organised accounting. It is not just an additional tax cost, but a critical factor in the financial planning and strategic management of any business. With the changes introduced by the State Budget for 2025, it becomes imperative for taxpayers to understand the new rules and adapt their strategies to optimise their tax burden.

This exhaustive guide aims to demystify Autonomous Taxation, with a particular focus on company vehicles, which represent one of the main sources of incidence. We will analyse the legal basis, applicable rates, covered charges, present practical examples and, crucially, outline tax optimisation strategies so that your company can navigate this complex tax landscape with confidence and efficiency.

1. What is Autonomous Taxation? Fundamental Concepts

Autonomous Taxation is a Portuguese tax mechanism that applies to certain expenses incurred by corporate income tax (IRC) taxpayers and, in specific cases, individual income tax (IRS) taxpayers with organised accounting. Its nature is distinct from traditional taxation on profit, as it does not depend on the existence of positive results for the company.

1.1. Nature and Purpose

Unlike IRC, which taxes the net profit of companies, Autonomous Taxation applies directly to certain categories of expenses, regardless of whether the company shows a taxable profit or loss. This characteristic makes it particularly onerous in years of negative results, as the company will have to pay tax even without having made a profit.

The main objective of Autonomous Taxation is to discourage certain expenses which, although tax deductible for the purpose of calculating taxable profit, are considered by the legislator to be less essential to business activity or likely to constitute forms of indirect remuneration for partners, managers, directors or employees. In this way, it seeks to ensure greater tax equity and combat potential abuses.

1.2. Distinction between IRC and IRS Taxpayers (Organised Accounting)

It is fundamental to distinguish the application of Autonomous Taxation according to the type of taxpayer:

• IRC Taxpayers (Companies): Autonomous Taxation is applied to a wide range of expenses, as detailed in Article 88 of the IRC Code.
• IRS Taxpayers with Organised Accounting (Self-Employed Individuals): For these taxpayers, Autonomous Taxation applies only to vehicle expenses, in accordance with Article 73 of the IRS Code. The other categories of expenses subject to AT for companies do not apply to self-employed individuals.

2. Legal Basis and Regulatory Framework

The Autonomous Taxation regime is established by various legal norms, the most relevant being:

• Article 88 of the IRC Code (CIRC): This is the central diploma for Autonomous Taxation applied to IRC taxpayers. It details the different categories of expenses subject to taxation and the respective rates.
• Article 73 of the IRS Code (CIRS): Defines the Autonomous Taxation rules applicable to IRS taxpayers with organised accounting, specifically regarding vehicles.
• Article 23 of the CIRC: This article is crucial for understanding the deductibility of expenses in general. Many expenses subject to Autonomous Taxation are only fiscally accepted within certain limits or conditions, which can aggravate the overall tax impact.
• Article 34 of the CIRC: Establishes the limits for the fiscal acceptance of depreciation of light passenger vehicles, which are one of the basic charges for calculating Autonomous Taxation.
• State Budget for 2025 (Law No. 45/2024): This diploma introduced the most recent changes to the rates and acquisition value thresholds for the 2025 tax year, which will be detailed in the following sections.

A deep understanding of these legal provisions is vital for correct framing and compliance with tax obligations, as well as for identifying optimisation opportunities.

3. Autonomous Taxation in 2025: Focus on Light Passenger Vehicles

Light passenger vehicles constitute one of the main focuses of Autonomous Taxation, representing a significant portion of tax costs for many companies. The State Budget for 2025 brought important new developments, with a review of rates and acquisition value thresholds.

3.1. IRC Taxpayers (Companies)

For companies, Autonomous Taxation rates on vehicles depend on the type of fuel and the acquisition value of the vehicle. The most recent changes aim to encourage the acquisition of more ecological vehicles.

3.1.1. Petrol or Diesel Vehicles (Art. 88, No. 1, al. a) of the CIRC)

• Acquisition value less than €37,500: Rate of 8%
• Acquisition value between €37,500 and €45,000: Rate of 25%
• Acquisition value equal to or greater than €45,000: Rate of 32%

Note: The acquisition value to be considered is the acquisition cost or the revaluation value, deducted from deductible VAT (Art. 88, No. 1, al. a) of the CIRC, in the wording updated by the OE 2025).

3.1.2. Plug-in Hybrid Vehicles (Art. 88, No. 1, al. b) of the CIRC)

Apply to vehicles with a minimum electric range of 50 km and CO2 emissions below 50 g/km.

• Acquisition value less than €37,500: Rate of 2.5%
• Acquisition value between €37,500 and €45,000: Rate of 7.5%
• Acquisition value equal to or greater than €45,000: Rate of 15%

3.1.3. CNG (Compressed Natural Gas) Vehicles (Art. 88, No. 1, al. c) of the CIRC)

Apply to vehicles powered exclusively by Compressed Natural Gas.

• Acquisition value less than €37,500: Rate of 2.5%
• Acquisition value between €37,500 and €45,000: Rate of 7.5%
• Acquisition value equal to or greater than €45,000: Rate of 15%

3.1.4. 100% Electric Vehicles (Art. 88, No. 1, al. d) of the CIRC)

• Acquisition value up to €62,500 (+ VAT): Not subject to Autonomous Taxation (total exemption).
• Acquisition value greater than €62,500 (+ VAT): Rate of 10%.

This exemption for electric vehicles up to a certain acquisition value is a significant incentive for electric mobility in companies.

3.2. IRS Taxpayers with Organised Accounting (Self-Employed Individuals)

For self-employed individuals (ENI) who opt for the organised accounting regime, the rules of Autonomous Taxation on vehicles are distinct and are provided for in Article 73 of the CIRS. It is important to note that AT for ENI is restricted to vehicles, not covering the other categories of expenses that affect companies.

3.2.1. Petrol or Diesel Vehicles (Art. 73, No. 1, al. a) of the CIRS)

• Acquisition value less than €30,000: Rate of 10%
• Acquisition value equal to or greater than €30,000: Rate of 20%

3.2.2. Plug-in Hybrid Vehicles (Art. 73, No. 1, al. b) of the CIRS)

Apply to vehicles with a minimum electric range of 50 km and CO2 emissions below 50 g/km.

• Acquisition value less than €30,000: Rate of 5%
• Acquisition value equal to or greater than €30,000: Rate of 10%

Note: 100% electric vehicles are exempt from Autonomous Taxation for ENI, regardless of the acquisition value (Art. 73, No. 1, al. c) of the CIRS).

3.3. Increased Rates in Case of Tax Loss

One of the most penalising characteristics of Autonomous Taxation is its increase in the event of a tax loss. In accordance with paragraph 14 of Article 88 of the CIRC, when the company presents a tax loss in the tax period to which the expenses relate, the Autonomous Taxation rates are increased by 10 percentage points.

Example: A diesel light passenger vehicle, with an acquisition value of €48,000, would be subject to the normal rate of 32%. If the company presents a tax loss, the applicable rate will become 42% (32% + 10%).

There are, however, exceptions to this increase, namely for the period of commencement of activity and the subsequent tax period, as provided for in the same paragraph 14 of Article 88 of the CIRC, provided that the company is not considered a large company (turnover greater than 50 million euros).

4. Charges Covered by Autonomous Taxation on Vehicles

Autonomous Taxation applies to a specific set of charges related to light passenger vehicles. It is fundamental to understand what these charges are for a correct calculation.

4.1. Detailed List of Charges

The charges that serve as the basis for calculating Autonomous Taxation, as per Art. 88, No. 1 of the CIRC, include:

• Depreciation or Amortisation: Includes the annual depreciation quotas of vehicles, fiscally accepted within the limits established by Article 34 of the CIRC and by Ordinance No. 467/2010. Even if the acquisition value of the vehicle exceeds the fiscal acceptance limit (e.g., €25,000 for combustion vehicles or €62,500 for electric vehicles), Autonomous Taxation applies to the entire depreciation fiscally accepted up to that limit.
• Rents or Leases: Cover financial leases (leasing), operating leases (renting) or long-term leases (ALD). In the case of financial leases, the part of the rent corresponding to depreciation or amortisation is considered. For renting/ALD, the entire rent is considered.
• Motor Vehicle Insurance: Mandatory and optional insurance premiums related to vehicles.
• Maintenance and Conservation: Includes expenses for servicing, repairs, parts replacement and other maintenance costs.
• Fuels: All expenses for fuel supply (petrol, diesel, CNG, electricity, etc.).
• Tolls: Costs for using motorways and other toll roads.
• Taxes: The Single Circulation Tax (IUC) and other taxes levied on the use of the vehicle.
• Other charges: Any other charges related to vehicles, provided they are deductible for IRC purposes.

4.2. Expenses Not Covered

It is important to note that Autonomous Taxation does not apply to all vehicle-related expenses. For example, parking expenses, as a rule, are not subject to Autonomous Taxation, unless they fall into another category of expenses subject to AT (e.g., representation expenses, if applicable).

5. Other Expenses Subject to Autonomous Taxation

In addition to vehicles, Article 88 of the CIRC lists other categories of expenses that are subject to Autonomous Taxation for IRC taxpayers. Understanding these categories is essential for comprehensive tax planning.

5.1. Representation Expenses (10%) (Art. 88, No. 1, al. e) of the CIRC)

Representation expenses are subject to a rate of 10%. These include, for example, costs with:

• Receptions, meals and trips offered to clients, suppliers or other business partners.
• Outings and shows provided as representation.
• Gifts and significant presents.

For these expenses to be accepted as such and to be deductible for IRC purposes (even if subject to AT), they must be duly documented and have a clear connection to the company's activity and its legitimate interest.

5.2. Undocumented Expenses (50%/70%) (Art. 88, No. 1, al. f) of the CIRC)

This category aims to discourage the existence of expenses without proper proof. Undocumented expenses, i.e., those for which there is no valid supporting document for tax purposes, are subject to a rate of 50%.

The rate increases to 70% if the expenses are incurred by taxpayers who are totally or partially exempt, or who do not primarily carry out commercial, industrial or agricultural activity (e.g., some associations, foundations).

5.3. Payments to Entities in Tax Havens (35%/55%) (Art. 88, No. 1, al. g) of the CIRC)

Payments to entities resident in countries, territories or regions with a clearly more favourable tax regime (the so-called "tax havens", whose list is approved by Ordinance of the Minister of Finance) are subject to Autonomous Taxation. The normal rate is 35%.

If, in addition to being made to an entity in a tax haven, these payments are not duly documented, the Autonomous Taxation rate increases to 55%.

5.4. Subsistence Allowances and Compensation for Travel in Own Vehicle (5%) (Art. 88, No. 1, al. h) of the CIRC)

This 5% rate applies to subsistence allowances and compensation for travel in the employee's own vehicle, when these expenses:

• Are not invoiced to clients (i.e., are not reimbursed by third parties).
• Are recorded as costs for the company's tax purposes.
• Have not been taxed under IRS in the beneficiary's (the employee's) sphere. This occurs when the amounts paid exceed the legal IRS exemption limits or when there is no travel log to justify the expense.

This measure aims to ensure that amounts paid to employees, which are not considered income for them, are not completely exempt from taxation.

5.5. Expenses with Bonuses and Indemnities to Managers (35%) (Art. 88, No. 1, al. i) of the CIRC)

Expenses with bonuses, premiums or other variable remuneration, as well as indemnities for termination of functions, attributed to managers, directors or administrators, are subject to a 35% Autonomous Taxation rate. This rate applies when the annual portion of these amounts is equal to or greater than 35% of the annual fixed remuneration and exceeds €27,500.

This measure seeks to limit tax deductibility and discourage the attribution of excessive variable remuneration to management positions, which could be used as a form of tax optimisation.

6. Practical Examples of Autonomous Taxation Calculation in 2025

To solidify understanding, we present practical scenarios with detailed calculations.

Example 1: Diesel Vehicle in a Company with Profit

Scenario: The company "TecnoSoluções, Lda." acquired in March 2025 a light diesel passenger vehicle, with an acquisition value of €42,000 (VAT included and fully deductible, so the base value for AT is €42,000). In the 2025 financial year, the company incurred the following expenses with this vehicle:

• Fiscally accepted depreciation (calculated on the limit of €25,000, since the vehicle is diesel): €25,000 * 25% = €6,250 (maximum annual depreciation quota).
• Financial lease rent (part corresponding to depreciation): €1,500
• Motor vehicle insurance: €950
• Maintenance and repairs: €1,800
• Fuel: €3,500
• Tolls and Parking (only tolls are relevant for AT): €600

The company obtained taxable profit in 2025.

Calculation:

1. Identification of expenses subject to AT:
   • Depreciation: €6,250
   • Rent (depreciation part): €1,500
   • Insurance: €950
   • Maintenance: €1,800
   • Fuel: €3,500
   • Tolls: €600
   Total expenses subject to AT = €6,250 + €1,500 + €950 + €1,800 + €3,500 + €600 = €14,600
2. Determination of the AT rate: The acquisition value of the vehicle (€42,000) falls between €37,500 and €45,000. For diesel vehicles, the applicable rate is 25%. As the company made a profit, there is no increase.
3. Calculation of Autonomous Taxation: Autonomous Taxation = €14,600 × 25% = €3,650

Example 2: Plug-in Hybrid Vehicle in a Self-Employed Individual with Loss

Scenario: A Self-Employed Individual (ENI), who carries out their activity with organised accounting, acquired in April 2025 a plug-in hybrid vehicle (with an electric range of 60km and CO2 emissions of 30g CO2/km) with an acquisition value of €32,000 (VAT not deductible, so the base value for AT is €32,000). In the 2025 financial year, the vehicle expenses were:

• Fiscally accepted depreciation (calculated on the limit of €37,500 for plug-in hybrids): €32,000 * 25% = €8,000
• Motor vehicle insurance: €700
• Maintenance: €1,000
• Fuel/Electricity: €2,000

The ENI presented a tax loss in 2025.

Calculation:

1. Identification of expenses subject to AT:
   • Depreciation: €8,000
   • Insurance: €700
   • Maintenance: €1,000
   • Fuel/Electricity: €2,000
   Total expenses subject to AT = €8,000 + €700 + €1,000 + €2,000 = €11,700
2. Determination of the AT rate: The acquisition value of the vehicle (€32,000) for ENI falls into the "equal to or greater than €30,000" category. For plug-in hybrids, the normal applicable rate is 10% (Art. 73, No. 1, al. b) of the CIRS). As the ENI had a tax loss, the rate is increased by 10 percentage points, becoming 20% (10% + 10%).
3. Calculation of Autonomous Taxation: Autonomous Taxation = €11,700 × 20% = €2,340

Example 3: Representation Expenses

Scenario: The company "Marketing Dinâmico, S.A." had expenses in 2025 for a client acquisition dinner amounting to €1,500, duly documented with an invoice in the company's name. The company obtained taxable profit.

Calculation:

1. Identification of expenses subject to AT: Representation expense = €1,500
2. Determination of the AT rate: For representation expenses, the rate is 10% (Art. 88, No. 1, al. e) of the CIRC). There is no increase for profit.
3. Calculation of Autonomous Taxation: Autonomous Taxation = €1,500 × 10% = €150

7. Autonomous Taxation Optimisation Strategies

Autonomous Taxation can represent a significant burden, but there are effective strategies to minimise it. Tax planning and informed decision-making are crucial.

7.1. Careful Choice of Vehicle Fleet

• Electric Vehicles: The total exemption from Autonomous Taxation for electric vehicles up to €62,500 (+ VAT) for companies and the total exemption for self-employed individuals (regardless of value) is a very attractive tax benefit. Above this value, the 10% rate for companies is still lower than most alternatives.
• Plug-in Hybrids: Represent a good compromise between electric mobility and range, with significantly reduced AT rates compared to combustion vehicles. It is essential to check the electric range and CO2 emission conditions to access these more favourable rates.
• Analysis of Acquisition Value Thresholds: A difference of a few euros in the acquisition value of a vehicle can mean a considerable jump in the Autonomous Taxation rate. For example, a diesel vehicle costing €37,000 pays 8%, while one costing €38,000 pays 25%. Careful analysis of these thresholds is essential before purchase.

7.2. Cost-Benefit Analysis between Purchase, Leasing and Renting

The form of acquisition or use of the vehicle impacts the basis for calculating Autonomous Taxation:

• Purchase: AT applies to depreciation and other charges. Depreciation is subject to fiscal acceptance limits (Art. 34 of the CIRC), which indirectly influences the AT base.
• Financial Lease (Leasing): AT applies to the part of the rent that would correspond to the depreciation of the asset, in addition to other charges.
• Operating Lease (Renting) or ALD: AT applies to the entire rent, in addition to other charges. Although renting rent is fully deductible for IRC (with limits for vehicles), its entirety is the basis for AT.

It is crucial to carry out a complete simulation, considering the total cost of the vehicle (acquisition/rents, maintenance, fuel, insurance) and the impact of Autonomous Taxation in each modality, to determine the most fiscally advantageous option.

7.3. Management and Prevention of Tax Losses

The 10 percentage point increase in Autonomous Taxation rates in the event of a tax loss can be extremely penalising. Companies should:

• Monitor the tax situation: Monitor provisional results throughout the financial year to anticipate the possibility of a tax loss.
• Expense Planning: Consider deferring discretionary expenses to years in which a taxable profit is expected, if feasible and does not compromise activity.
• Revenue Optimisation: Seek ways to anticipate revenues or concentrate them in years of potential loss to avoid it.

7.4. Rigorous Expense Control and Documentation

• Complete Documentation: Ensure that all expenses (especially representation and vehicle-related expenses) are duly documented with valid invoices or receipts. The absence of documentation can lead to the application of the increased rate of 50% (or 70%) for undocumented expenses, in addition to making them non-deductible for IRC.
• Expense Justification: In the case of subsistence allowances and use of own vehicle, it is fundamental to maintain detailed travel logs and other evidence that justify the amounts paid and their non-taxation under IRS in the employee's sphere, to avoid the application of the 5% rate.

7.5. Analysis of Additional Tax Benefits

In addition to Autonomous Taxation, the choice of electric or plug-in hybrid vehicles can bring other tax benefits, such as VAT deduction under certain conditions (Art. 21 of the CIVA) or benefits under the Tax Benefits Statute (EBF), which should be considered in the overall analysis.

8. Declaration and Payment of Autonomous Taxation

Autonomous Taxation, although a distinct tax from IRC, is assessed and paid together with it.

8.1. Model 22 Declaration

The calculated Autonomous Taxation amounts must be included in the Periodic Income Statement (Model 22) of IRC. There are specific fields in this declaration for the breakdown of the different categories of Autonomous Taxation, allowing their identification separately from IRC on taxable profit.

Model 22 must be submitted electronically by the last day of May of the year following the one to which the tax relates (or by the 5th month after the end of the tax period, if it does not coincide with the calendar year).

8.2. Payment Deadline and Method

The payment of Autonomous Taxation must be made by the last day of the deadline for submitting the Model 22 Declaration. It is important to note that, unlike IRC on profit, Autonomous Taxation is not eligible for payment in instalments. The total amount calculated must be paid in full within the established deadline.

9. Common Mistakes to Avoid in Managing Autonomous Taxation

The complexity of Autonomous Taxation often leads to errors that can result in fines and additional costs. Knowing the most common errors helps prevent them.

• Ignorance of Acquisition Value Thresholds: Acquiring a vehicle slightly above one of the value thresholds can have a disproportionate impact on the AT rate. Many companies fail to analyse this crucial aspect at the time of purchase.
• Failure to Consider the Loss Surcharge: Ignoring the 10% increase in rates in years of tax loss is a common mistake that can lead to significant underestimations of the tax cost. Continuous monitoring of results is vital.
• Lack of Adequate Documentation: Not having valid invoices or receipts for expenses (especially representation or other expenses) or not keeping detailed records for subsistence allowances can result in the application of higher AT rates (50%/70%) and non-deductibility for IRC.
• Misinterpretation of Covered Charges: Not all costs associated with a vehicle are subject to AT. For example, parking expenses or tolls on heavy vehicles are not subject. Incorrect interpretation can lead to erroneous calculations.
• Confusing IRC and IRS Rules: AT rules for companies (IRC) and for self-employed individuals with organised accounting (IRS) are distinct, especially regarding the categories of expenses covered and the rates. It is fundamental to apply the correct regime to each taxpayer.
• Disregarding Deductible VAT in the Calculation Basis: For the purpose of calculating the acquisition value of the vehicle (which determines the AT rate), the acquisition cost deducted from deductible VAT must be considered. Errors in this calculation can lead to the application of an incorrect rate.
• Failure to Optimise Vehicle Type Choice: Maintaining a fleet of combustion vehicles without analysing the tax advantages of electric or plug-in hybrid vehicles represents a lost opportunity for significant tax savings.

10. Conclusion: Planning as Key to Tax Efficiency

The changes introduced by the State Budget for 2025 to Autonomous Taxation, although bringing some flexibility and incentives for green mobility, confirm that this tax mechanism continues to be a substantial burden for companies in Portugal. Its nature, which applies to expenses and increases in the event of a loss, requires constant attention and rigorous planning.

Investing in electric or plug-in hybrid vehicles is, without a doubt, the most advantageous strategy from a tax perspective, aligning with environmental and sustainability concerns. However, even for combustion vehicles, proactive management, including the analysis of acquisition value thresholds and the monitoring of tax results, can generate significant savings.

It is imperative that companies and self-employed individuals under the organised accounting regime do not view Autonomous Taxation as merely an unavoidable cost, but rather as an area where optimisation can have a direct impact on profitability. Correct documentation of expenses, understanding limits and informed choice of the vehicle fleet are pillars of efficient tax management.

At HVR Business Consulting, we are specialists in Portuguese accounting and taxation. We help our clients navigate the complexity of the tax system, identifying optimisation opportunities, ensuring compliance with all legal obligations and minimising risks. If your company wishes to review its tax strategy regarding Autonomous Taxation or needs specialised support, please contact us for a free tax diagnosis. We are here to ensure your business thrives with maximum tax efficiency.

11. Sources and Legal References

• Article 88 of the IRC Code (CIRC) - Autonomous Taxation Rates (corporate taxpayers)
• Article 73 of the IRS Code (CIRS) - Autonomous Taxation Rates (self-employed individuals with organised accounting)
• Article 23 of the IRC Code (CIRC) - Deductible expenses and losses
• Article 34 of the IRC Code (CIRC) - Limits for fiscal acceptance of depreciation of light vehicles
• Article 21 of the VAT Code (CIVA) - Limits on VAT deduction for vehicles
• Law No. 45/2024 (State Budget for 2025) - Changes to Autonomous Taxation rates and thresholds
• Ordinance No. 467/2010, of 7 July - Establishes depreciation rates and fiscal acceptance limits for vehicles
• Tax Benefits Statute (EBF) - Various tax incentives, including for electric vehicles
• Labour Code - Rules for subsistence allowances and compensation for use of own vehicle (indirectly relevant for AT)