Modello CU (Certificazione Unica)

The Modello CU, officially called the Certificazione Unica, is Italy’s annual income certification document. It is issued by a withholding agent, known in Italian as the sostituto d’imposta, to confirm the income paid and taxes withheld during the previous calendar year.

The Certificazione Unica replaced the former CUD, Certificazione Unica Dipendente, in 2015. Unlike the old CUD, which mainly covered employment and pension income, the CU has a wider scope. It can include income paid to employees, pensioners, freelancers, professionals, agents, commission earners, and other recipients.

For employees and other income recipients, the CU acts as official proof of annual earnings, tax withholdings, and social security information. For the Italian tax authority, the Agenzia delle Entrate, it provides essential data used to prepare the 730 precompilato, Italy’s pre-filled income tax return.

For employers and international companies operating in Italy, the Modello CU is a key year-end payroll and tax compliance obligation. It connects payroll reporting, IRPEF withholding, social security contributions, and annual tax reconciliation.

What Is the Certificazione Unica?

The Certificazione Unica is an official tax certificate issued each year by Italian withholding agents. It reports the income paid to a recipient and the related taxes and contributions withheld during the previous tax year.

The document is governed by Italian tax rules, including D.P.R. No. 322 of 22 July 1998, and is updated annually through instructions and technical specifications issued by the Agenzia delle Entrate.

The CU is used to certify:

• Employment income, known as redditi di lavoro dipendente
• Income treated as employment income, known as redditi assimilati
• Pension income
• Self-employment and professional income
• Commissions paid to agents and intermediaries
• Occasional work and other taxable income
• Short-term rental income where applicable
• IRPEF tax withholdings
• Regional and municipal tax surcharges
• Social security and welfare-related data

In practice, the Modello CU works as both an income certificate for the recipient and a reporting file for the Italian tax administration.

Why the Modello CU Matters

The Modello CU is important because it supports several core functions of the Italian tax system.

For income recipients, it helps verify annual income, taxes withheld, deductions, tax credits, and social security data. It is also commonly used when applying for loans, mortgages, visas, social benefits, or ISEE certification.

For the Agenzia delle Entrate, CU data is used to pre-fill tax returns and cross-check information submitted by employers, pension institutions, and other withholding agents.

For employers, the CU is part of a wider compliance framework that also includes monthly payroll calculations, UNIEMENS social security reporting to INPS, and annual Modello 770 filing.

CU Sintetica and CU Ordinaria

The Certificazione Unica has two main versions: CU Sintetica and CU Ordinaria. Both relate to the same income data, but they serve different purposes.

CU Sintetica

The CU Sintetica is the simplified version given to the income recipient. It is designed to be easier to read and includes the main information needed by the employee, pensioner, freelancer, or other beneficiary.

Recipients use the CU Sintetica to:

• Check income earned during the previous year
• Review IRPEF and other tax withholdings
• Compare income data with the 730 precompilato
• Prepare a Modello 730 or Modello Redditi
• Apply for ISEE or other social benefits
• Provide income evidence to banks, authorities, or third parties

CU Ordinaria

The CU Ordinaria is the full technical version sent electronically to the Agenzia delle Entrate. It includes all information contained in the CU Sintetica, plus additional tax, identification, and transmission data required by the tax authority.

The CU Ordinaria may include:

• Full recipient and withholding agent details
• Detailed income and withholding data
• Technical tax codes and reporting fields
• The Frontespizio, or cover sheet
• Quadro CT, where required
• Data needed for the 730 precompilato
• Information used for checks against UNIEMENS and Modello 770

This two-version structure allows recipients to receive a readable document while the tax authority receives the detailed data needed for automated processing.

Who Must Issue the Modello CU?

The obligation to issue the Certificazione Unica applies to any Italian withholding agent that pays income subject to withholding tax.

This may include:

• Italian companies paying employees
• Public-sector employers
• Foreign companies with a permanent establishment in Italy
• INPS and other pension providers
• Professional firms paying freelancers or consultants
• Companies paying agents, brokers, or commission earners
• Real estate intermediaries and platforms involved in short-term rentals
• Condominiums and other entities required to withhold tax on certain payments

A CU may need to be issued to:

• Employees
• Pensioners
• Interns and collaborators
• Directors and public office holders
• Freelancers with a partita IVA
• Professionals and consultants
• Sales agents and representatives
• Recipients of occasional self-employment income
• Other recipients of taxable or reportable income

For multinational employers, this means that CU compliance must cover not only employees but also other worker and payment categories that fall within Italian withholding rules.

Information Included in the Certificazione Unica

The Modello CU contains personal, tax, payroll, and social security information. Accuracy is essential because errors can affect the recipient’s tax return and the employer’s annual reporting.

Identification Data

The CU includes identification details for both the withholding agent and the recipient, such as:

• Codice Fiscale of the employer or withholding agent
• Codice Fiscale of the recipient
• Name, surname, date of birth, and place of birth
• Residence details
• Tax domicile at relevant dates
• Italian or foreign tax residence status
• Dependent family member information where applicable

Tax domicile data is especially important because it affects regional and municipal surcharge calculations.

Employment Income Data

For employees and similar workers, the CU may report:

• Total taxable employment income
• IRPEF withheld during the year
• Employment-related tax deductions
• Family-related deductions
• Regional surcharge
• Municipal surcharge
• Trattamento Integrativo, also known as Bonus IRPEF
• Productivity bonuses subject to substitute tax
• Tax adjustments and recoveries
• Days worked for tax credit calculations
• Fringe benefits and welfare benefits

Self-Employment and Other Income Data

For freelancers, consultants, and other non-employee recipients, the CU may include:

• Gross compensation paid
• Withholding tax applied
• INPS Gestione Separata contributions where relevant
• Commissions paid to agents and intermediaries
• Occasional work income
• Short-term rental income where applicable
• Other income categories reportable under Italian tax law

Social Security and Welfare Data

The Certificazione Unica may also include:

• INPS contribution data
• Employer and employee social security contributions
• TFR, or Trattamento di Fine Rapporto
• Severance and termination payments
• Supplementary pension contributions
• Welfare benefits
• Fringe benefits within or above statutory limits

Annotations

The annotations section contains explanatory notes and codes. These may clarify tax treatments, substitute taxation, adjustments, special income categories, or data relevant to the recipient’s tax return.

How the CU Supports the 730 Precompilato

The Modello CU is one of the main data sources for the 730 precompilato, Italy’s pre-filled tax return.

After the CU Ordinaria is submitted, the Agenzia delle Entrate uses the data to prepare the taxpayer’s pre-filled return. This information may be combined with data from banks, insurance companies, healthcare providers, pension institutions, and other reporting entities.

Taxpayers can access the pre-filled return through digital identity tools such as SPID, CIE, or CNS. They can then accept, edit, or replace the return.

Because CU data flows directly into the pre-filled tax return, errors in the CU can create problems for the employee or recipient. Incorrect income, tax, or deduction data may require manual correction and can delay tax filing.

How to Access the Certificazione Unica

Recipients can obtain their CU through several channels, depending on who issued the document.

Common access methods include:

• Direct delivery by the employer or withholding agent
• Electronic delivery through a company HR or payroll portal
• Agenzia delle Entrate online services
• INPS portal for pensioners and benefit recipients
• INPS Mobile app
• PEC request for certain INPS-issued documents
• Authorised intermediaries such as CAF offices, accountants, or patronati

Employees usually receive the CU directly from their employer, while pensioners typically access it through INPS.

Common Modello CU Updates

The CU model is updated regularly by the Agenzia delle Entrate. Annual changes may reflect new tax brackets, updated benefits rules, new reporting codes, or changes to filing specifications.

Recent CU updates have focused on areas such as:

• Trattamento Integrativo reporting
• IRPEF tax bracket changes
• Productivity bonuses and substitute tax treatment
• Welfare benefits and fringe benefit thresholds
• Short-term rental income reporting
• Quadro CT requirements
• Self-employment reporting deadlines
• Alignment with 730 precompilato data requirements

Employers should review the updated CU instructions every year before preparing the annual filing.

Penalties for Modello CU Non-Compliance

Italian tax authorities apply penalties when the Certificazione Unica is late, omitted, incomplete, or incorrect.

Common compliance risks include:

• Late transmission of the CU Ordinaria
• Failure to transmit the CU Ordinaria
• Failure to deliver the CU Sintetica to the recipient
• Incorrect recipient identification data
• Incomplete income or withholding information
• Errors affecting the 730 precompilato
• Late correction of inaccurate data
• Differences between CU, UNIEMENS, and Modello 770 data
• Late or unpaid withholding taxes

Penalties can apply per certification, and repeated errors may increase the risk of tax reviews or inspections.

Common CU Mistakes to Avoid

Employers and payroll teams should carefully review CU data before submission. Frequent errors include:

• Incorrect Codice Fiscale
• Wrong tax domicile
• Missing dependent family member data
• Incorrect IRPEF withholding figures
• Errors in regional or municipal surcharge calculations
• Misclassification of income type
• Missing annotations or incorrect codes
• Incorrect treatment of welfare benefits
• Incomplete TFR reporting
• Failure to reconcile CU data with UNIEMENS
• Inconsistencies between CU and Modello 770
• Missing Quadro CT where required
• Late delivery to recipients

A strong year-end payroll reconciliation process can reduce these risks significantly.

Modello CU and Italian Payroll Compliance

The Certificazione Unica is only one part of Italy’s broader payroll compliance framework. Employers must also manage monthly payroll, IRPEF withholding, INPS contributions, INAIL insurance, TFR accruals, collective bargaining obligations, UNIEMENS filings, and Modello 770 reporting.

Italy’s payroll environment can be complex, especially for international companies managing local employees, freelancers, or remote teams. Employers must account for national legislation, regional and municipal taxes, sector-specific collective bargaining agreements, and annual tax authority updates.

This makes CU preparation a critical year-end task. Accurate CU reporting helps ensure employees receive correct income documentation, tax returns are pre-filled correctly, and employer filings remain aligned across payroll, social security, and tax systems.

How Mercans Supports Modello CU Compliance

Managing the Modello CU, Certificazione Unica, is only one part of Italy’s wider payroll and tax compliance framework. Employers must also handle IRPEF withholdings, INPS social security contributions, INAIL insurance, TFR accruals, UNIEMENS reporting, Modello 770 filing, and sector-specific CCNL obligations.

For international employers, these requirements can be difficult to manage without local payroll expertise. Mercans’ Italy Employer of Record services help companies hire employees in Italy without setting up a local legal entity, while ensuring payroll, employment contracts, tax withholding, and statutory reporting remain compliant with Italian regulations.

Companies that already have an entity in Italy can use Mercans’ global payroll services to manage local payroll processing, CU preparation, tax reporting, and year-end payroll compliance. Mercans supports accurate gross-to-net calculations, IRPEF withholding, regional and municipal surcharge management, INPS and INAIL compliance, and annual reporting obligations such as the Certificazione Unica and Modello 770.

Through HR Blizz, Mercans also helps employers centralize payroll data, employee records, reporting, and compliance workflows across multiple countries. This is especially valuable for multinational companies that need consistent payroll visibility while meeting Italy-specific requirements.

Mercans’ Italy payroll support can include:

• Italian payroll processing
• CU Sintetica preparation and delivery
• CU Ordinaria preparation and electronic submission support
• Modello 770 support
• UNIEMENS reporting support
• IRPEF withholding calculations
• Regional and municipal surcharge management
• INPS and INAIL compliance support
• TFR calculation and reporting
• CCNL-based payroll compliance
• Employer of Record support in Italy
• Payroll reporting through Mercans’ global HR and payroll technology

With payroll coverage across more than 160 countries, Mercans supports employers that need accurate, compliant, and scalable payroll operations in Italy and worldwide. Explore Mercans’ payroll and EOR solutions to simplify Modello CU compliance and manage Italian payroll with confidence.

Modello CU FAQs

What is the Modello CU?

The Modello CU, or Certificazione Unica, is Italy’s annual income certification document. It reports income paid and taxes withheld by a withholding agent during the previous calendar year.

What does CU mean in Italy?

CU stands for Certificazione Unica, which means Single Certification. It replaced the previous CUD system and now covers a wider range of income types.

Who issues the Certificazione Unica?

The CU is issued by a sostituto d’imposta, or withholding agent. This may be an employer, pension institution, company, professional firm, or other entity that pays income subject to withholding tax.

Who receives a CU?

Employees, pensioners, freelancers, consultants, agents, commission earners, and other income recipients may receive a CU if they were paid income that must be certified under Italian tax rules.

What is the difference between CU Sintetica and CU Ordinaria?

The CU Sintetica is the simplified version given to the recipient. The CU Ordinaria is the detailed version sent electronically to the Agenzia delle Entrate.

When is the CU issued?

The CU is generally delivered to recipients by 16 March of the year following the income year. If the date falls on a weekend or public holiday, the deadline usually moves to the next working day.

Can freelancers receive a CU?

Yes. Freelancers and professionals with a partita IVA may receive a CU from clients that paid them income subject to withholding tax.

How is the CU used in the 730 precompilato?

The Agenzia delle Entrate uses CU Ordinaria data to prepare the taxpayer’s pre-filled tax return. Incorrect CU data can therefore affect the accuracy of the 730 precompilato.

What should I do if my CU is wrong?

The recipient should contact the employer or withholding agent and request a corrected CU. The withholding agent may need to reissue the CU and transmit corrected data to the Agenzia delle Entrate.

How long should a CU be kept?

Recipients should keep their CU for several years in case of tax checks, income verification requests, or social benefit applications. A retention period of at least six to eight years is commonly recommended.