ISA Reliability Scores: What Your Tax Score Means and What's at Stake

In a Nutshell

ISA — Indici Sintetici di Affidabilità (Italy's synthetic fiscal reliability indices) — is the system Agenzia delle Entrate (Italy's tax-revenue agency) uses to assign a score from 1 to 10 to your annual tax return. The score is calculated by comparing your numbers against those of other businesses in your same sector. Score high and you get real perks: fewer audits, faster VAT refunds, fewer guarantee requirements. Score low and you land on a risk watchlist. ISA replaced the older studi di settore (sector studies) system in 2018 and is mandatory for nearly all Partita IVA (Italian VAT number — required to invoice as a self-employed worker) holders, with flat-rate taxpayers being the main exception.

At a Glance

Cost	Free (downloadable software from the Agenzia delle Entrate website). Having an accountant handle it: typically included in their fee, or €50–200 extra
Deadline	Filed alongside your annual tax return — standard deadline: 30 September
In Rome	7 Agenzia Entrate offices for assistance. Accountants and some CAF (free assistance offices for tax and benefits forms) for sole traders
Software	"Il tuo ISA" — free download from the Agenzia delle Entrate

How the Score Works

The free software "Il tuo ISA", downloadable from Agenzia delle Entrate, processes both accounting and non-accounting data from your business and generates a score.

The system evaluates multiple reliability indicators — revenue per employee, value added per employee, profit per employee, inventory turnover — alongside anomaly indicators such as disproportionate costs, inconsistent stock management, and a high share of undocumented expenses. Each indicator gets a score from 1 to 10, and the weighted average becomes your final ISA score.

What the score means in practice:

• Score 8 or above: you're "reliable" — you qualify for the benefits listed below
• Score 6 to 8: normal range, no bonuses or automatic penalties
• Score below 6: considered at risk; you may appear on control watchlists
• Score below 4: high risk of written enquiries or summons from the Agenzia

The Real Perks of a High Score

Hitting 8 or above isn't just a badge of honour — it unlocks concrete tax advantages.

With a score of 8 or above you can:

• Offset IRPEF (Italian personal income tax) / IRES (Italian corporate income tax) / IRAP (regional production tax) credits up to €20,000 without a conformity visa
• Offset IVA (Italian VAT) credits up to €50,000 without a conformity visa
• Claim IVA refunds up to €50,000 without providing bank guarantees
• Be excluded from analytical-inductive assessments (art. 39, DPR 600/1973)
• Benefit from a one-year reduction in the audit limitation period (from 5 to 4 years)
• Be excluded from the dormant-company (società di comodo) regime

With a score of 9 or above in the current and previous year, you're also excluded from assessments based on simple presumptions.

What's at Risk with a Low Score

A low score alone is not automatic grounds for a tax audit. ISA guides audit targeting; it doesn't trigger assessments directly. That's the key difference from the old studi di settore system.

Score below 6 and you enter the Agenzia's selective lists, making it more likely you'll be contacted for a meeting or a questionnaire. Score below 4 consistently for multiple years and the risk of an official assessment climbs significantly.

Context matters: if your low score has a clear explanation — for instance, you run a gym and your 2020–2021 figures benefited from the extraordinary Covid corrections — the situation is very different from having incoherent numbers with no recognisable cause.

Voluntary Top-Up: Declaring More to Raise Your Score

If your score comes out low, you have the option to voluntarily declare additional income above what your accounts show, by flagging "further positive components" in your return. This lifts your ISA score and reduces audit risk.

The trade-off: you pay IRPEF (or IRES), IRAP, IVA and contributions on the extra amount declared. If the top-up exceeds a certain percentage of what you originally declared, a 3% surcharge applies. Before topping up blindly, sit down with your accountant and compare the real cost of the adjustment against the actual probability of an audit.

Who Must File ISA

You must complete ISA if you hold a Partita IVA with revenues or fees up to €5,164,569 per year and your ATECO code (Italy's business activity classification) is among the 175 approved ISA models.

You are exempt if:

• You're on the flat-rate regime (regime forfettario, Legge 190/2014) — ISA doesn't apply to you
• It's your first year of activity
• You're in your final year (cessation of activity)
• The business is in liquidation, bankruptcy or creditors' arrangement
• Your revenues exceed €5,164,569
• You're part of a non-profit (Terzo Settore or ONLUS)

Getting It Right: How to Fill It In

Each ATECO code has its own ISA model (e.g. AG40U for hairdressers, CG36U for restaurants, WK02U for IT consultants). You file the model that corresponds to your primary ATECO code.

Beyond the accounting figures — revenue, costs, fixed assets — the software asks for sector-specific non-accounting data: number of employees and hours worked, floor space, type of clientele (private individuals or businesses), percentage breakdown of services offered, premises type (owned or rented). Leave these fields blank and the system scores you on incomplete data — which almost always means a lower score than you actually deserve.

Mistakes to Avoid

1. Wrong or outdated ATECO code. If your actual activity doesn't match the code on file, you'll score low for a structural reason that has nothing to do with your real numbers. Verify your code and update it via the Camera di Commercio (Chamber of Commerce) and Agenzia delle Entrate if needed.
2. Leaving non-accounting fields blank. Many people fill in the financial figures and skip the non-accounting sections. The result is an artificially low score. Fill in everything, including fields that seem marginal.
3. Topping up without running the numbers. Declaring extra income to raise your score costs real taxes. Calculate the cost of the adjustment and compare it to the realistic risk of an audit before committing.

Special Cases

Covid years (2020–2021): The Agenzia issued extraordinary corrections for the hardest-hit sectors — restaurants, tourism, gyms, entertainment. If your business fell into one of those categories, scores for those years were automatically adjusted upward.

Multiple activities with different ATECO codes: ISA applies to your primary ATECO code — the one that accounts for the majority of your revenue.

Non-calendar fiscal year (e.g. July–June): ISA is calculated over the declared tax period, not the calendar year.

Activity started after April: If you traded for fewer than 12 months during the year, ISA filing is excluded (reason code: ISA-CA "activity started or ceased during the year").

Official Sources

• Agenzia Entrate — ISA (main page)
• Agenzia Entrate — ISA 2024
• Software "Il tuo ISA"
• Sose Spa — ISA processing
• Normattiva — DL 50/2017
• Normattiva — DPR 600/1973

Legal references: DL 50/2017 art. 9-bis, Legge 96/2017, DM 23/03/2018, DPR 600/1973 art. 39, annual Agenzia delle Entrate directives.