Work Accident Rate 2026: Understanding Tarification and Reducing Your Contribution

The occupational accident and disease contribution (AT/MP) is the only social contribution whose rate depends directly on your company's claims history. Many business owners simply pay it without ever reading it. At Hayot Expertise, we regularly help clients decode this rate and use the right prevention levers to bring it down sustainably.

Quick answer. In 2026, the net AT/MP rate is calculated as (base rate + 0.19%) × (1 + 52%) + 0.17% + 0.03%, using the fixed surcharges M1 to M4 set by the order of 30 December 2025. The tarification mode depends on headcount: collective below 20 employees, mixed from 20 to 149, individual from 150. The rate is notified each year on the AT/MP account at net-entreprises.fr. The contribution is borne entirely by the employer, and a recognised prevention policy can earn a rebate of up to 25%.

Every employer contributes to the AT/MP branch of social security, managed by the Health Insurance – Occupational Risks division (CNAM and the Carsat network). Unlike other social contributions, the AT/MP rate is not uniform: it reflects your company's actual risk, measured by your history of recognised workplace accidents and occupational diseases.

This mechanism is deliberately incentive-based: preventing accidents lowers your contribution. A company with no claims for several years pays significantly less than one where work stoppages multiply. It is therefore a cost you can steer, provided you understand it and fold it into your employer social obligations.

Three tarification modes by headcount#

The tarification mode depends solely on the company's average headcount:

Classification on 1 January each year is based on the prior year's average headcount. A change of mode is therefore never automatic when a threshold is crossed: it is assessed on the annual average headcount.

Your AT/MP rate is not a single figure. It combines a base rate (driven by your activity and, depending on the mode, your claims history) and four national fixed surcharges, set each year by ministerial order.

In 2026, these surcharges come from the order of 30 December 2025:

The net rate is calculated as: net rate = (base rate + M1) × (1 + M2) + M3 + M4, i.e. in 2026: (base rate + 0.19%) × 1.52 + 0.17% + 0.03%. For reference, the national average net rate stands at 2.08% for 2026. At Hayot Expertise, we systematically break this composition down in your payroll statements.

Reading your AT/MP account on net-entreprises.fr#

Consulting the rate is fully digital. Your notified rate is available on the AT/MP account, integrated into the company account on net-entreprises.fr:

1. log in to your company account on net-entreprises.fr;
2. open the "View your AT/MP rates and prevent occupational risks" service;
3. you will find your tarification mode, your current net rate, the calculation detail and your rate history.

Failure to enrol in the AT/MP account can trigger a penalty (up to €10,000 per year depending on headcount). The notified rate then applies automatically to your payslips through the DSN.

An employer-only contribution#

A key point: the AT/MP contribution is borne entirely by the employer. There is no employee share, unlike health insurance or pension contributions. The annual contribution equals: gross payroll × net AT/MP rate (the M1 to M4 surcharges are already built into that net rate).

For a 30-employee SME with a 2% net rate, the contribution represents 2% of gross payroll. Cutting that rate from 2% to 1.8% through prevention saves 0.2 of a point across the entire payroll — far from negligible, including from the first hire.

1. The Carsat prevention rebate#

When your prevention efforts exceed those of your sector, the Carsat can grant a rebate on your net rate, capped at 25%. Conversely, a deteriorated claims record or exceptional risks may justify an additional contribution (surcharge). The rebate is notified directly on your AT/MP account.

2. Financial prevention aids (very small and small businesses)#

The Health Insurance – Occupational Risks division offers Prevention Subsidies reserved for companies with fewer than 50 employees, to fund equipment or targeted prevention actions:

• safety diagnostics and audits;
• occupational risk prevention training;
• protective equipment and ergonomic improvements.

Their amount usually corresponds to a share of the pre-tax investment, within a cap set by the AT/MP branch, and varies by current programme. These aids can be combined with a rebate.

3. The prevention contract#

For companies with fewer than 200 employees in a branch that has signed a national objectives agreement, the prevention contract formalises, with the Carsat, an action programme over a fixed period. It may include a financial advance, convertible into a subsidy when objectives are met.

Process:

1. contact your regional Carsat;
2. set out your activity and safety priorities;
3. build a costed action plan;
4. sign the contract and implement the actions, with supporting evidence.

High-risk sectors#

Some sectors (the construction industry, hospitality, handling, transport) display naturally higher rates because of inherent risk. These rates are not a penalty: they reflect the sector's real claims experience. This is precisely where prevention generates the most visible savings.

Change of tarification mode#

When moving from one mode to another (collective to mixed, or mixed to individual), the rate may initially rise, because your own claims history becomes decisive. Anticipating prevention before crossing a threshold cushions this effect.

Multiple establishments#

A company with several establishments may be assigned distinct rates per establishment, depending on activity and location, since each establishment falls under the Carsat of its region.

1. Check your rate from January. The rate is updated on 1 January. Verify the mode, the net rate and the surcharges on net-entreprises.fr.
2. Do not confuse the funds. The CPAM investigates and recognises the workplace accident; the Carsat calculates and notifies the AT/MP rate. A workplace accident declaration (DAT) is filed with the CPAM within 48 hours, never with the Carsat.
3. Handle your declarations carefully. A recognised claim weighs on your rate for three years. Where justified, filing motivated objections at declaration can avoid an undue recognition — and therefore an undue surcharge.
4. Document your prevention. Supporting evidence (training, equipment, audits) conditions aids and rebates; the occupational health monitoring of employees is part of this.
5. Contest errors within the deadline. The notified rate can be challenged within a two-month appeal period.

At Hayot Expertise, we supported a 45-employee logistics company in mastering its AT/MP rate. The Carsat showed a net rate of 2.8% — above its sector average — after three workplace accidents in two years. The director believed this rate was permanently imposed.

We launched a multi-year prevention programme with the Carsat (ergonomics audit, safety training, anti-tip warehouse equipment) and tightened declarations, contesting the classification of one claim wrongly recorded as a workplace accident. Three years later, the rate was down to 1.8%, an annual saving of around €15,000 on a €1.5M payroll.

Our conviction: the AT/MP rate is not a fatality. It results from a coherent strategy — identifying risks, visible prevention, reliable declarations and regular monitoring of the AT/MP account. Most directors do not realise this rate can move in their favour.

Hayot Expertise advice. Check your AT/MP account every January. If the rate surprises you, do not accept it passively: compare it with your sector average and start a prevention process with your Carsat. Our chartered accountancy firm audits the account, builds the prevention scenario and steers the file alongside you.