INPS Enhances Tax Compliance with ISACs and Compliance Letters

The Italian National Social Security Institute (INPS) is bolstering efforts to improve tax compliance through the implementation of Synthetic Indices of Contribution Reliability (ISACs) and the issuance of compliance letters. Beginning January 1, 2026, these measures aim to identify and address undeclared work, starting with the hotel and large-scale food distribution sectors, with plans for expansion to other industries.

What are ISACs?

ISACs are statistical-economic indicators designed to assess the consistency between declared employment and actual business activity. They combine contributory and fiscal data to verify the adequacy of the workforce reported by employers [INPS]. The purpose is to prevent underreporting of taxable bases and ensure accurate social security contributions.

Compliance Letters and the SEND Platform

INPS is sending compliance letters to companies in the food wholesale trade and hotel/accommodation sectors. These letters, delivered via the SEND platform, provide a snapshot of the company’s contribution status. Over 12,000 letters were scheduled for distribution in March 2026, addressing positions analyzed from a total of 33,732 [Il Sole 24 Ore].

It’s important to note that these letters are not formal assessment notices and do not automatically indicate irregularities. Instead, they serve as an invitation for companies to review their practices and ensure compliance with labor legislation.

What Information is Included in the Compliance Letters?

Each compliance letter includes:

• Normal Values: Thresholds indicating when an indicator generates a deviation.
• Outcome: A classification of the condition as “normal,” “slight deviation,” or “significant deviation.”
• Estimate of Working Days: An estimate of the number of working days needed to bring the indicator back into the normal range.

The Role of the ISAC Model and INL

Employers who comply with the ISAC model, without “slight” or “significant” deviations, are considered within the “normal range.” INPS transmits a list of these compliant employers to the Ministry of Labor and Social Policies and the National Labor Inspectorate (INL) to inform and guide supervisory activities related to contributions [Il Sole 24 Ore].

Employer Response and Dialogue with INPS

Employers receiving compliance letters are encouraged to evaluate their adherence to labor laws and make necessary adjustments. They can provide additional data to INPS or request clarifications on the ISACs through the social security drawer. There are no specific deadlines or requirements for responding to the letters.

Background and Implementation

The introduction of ISACs was initiated on an experimental basis as part of the National Recovery and Resilience Plan (PNRR). The initial focus on the food wholesale and hotel sectors reflects their perceived higher risk of tax evasion and avoidance [Il Sole 24 Ore].

Social Security Contributions for Executives in 2026

Social security contributions for executives (dirigenti) in 2026 are as follows: INPS contributions are 9.19% on income up to EUR 55,448, and 10.19% on income exceeding that amount [PwC]. The maximum cap for FY 2026 will be made available by the end of January.

The total social security rate is around 40% of the employee’s gross compensation, shared approximately 30% for the employer and 10% for the employee [PwC].

Contribution Rates Overview

The overall contribution rate is determined by the sum of applicable insurance schemes, including Invalidity, Ancient Age and Survivors, Unemployment Insurance, Illness, and the Wage Compensation Fund [INPS]. The contribution rate for pension purposes for employees is 33%, with special arrangements for certain categories like postal workers and flight crews.