If you have ever been posted to another EU country for work, or if your HR team routinely sends staff across borders, a quiet but consequential change is coming. The rules that decide which country collects your social contributions during a posting are being rewritten, and the clock on the transition has already started.

In April 2026, the European Union reached a provisional agreement on the revision of its social security coordination legislation. On 7 July 2026, the European Parliament adopted amendments to Regulation (EC) 883/2004 on the coordination of social security systems, together with implementing Regulation (EC) 987/2009. The revised text, together known as the Coordination Regulation, enters into force on the first day of the month following its publication.

The headline change most employers care about, the new Article 12 governing posted workers, applies only from July 2028, twenty-four months after the regulation enters into force. During that two-year transition, the old rules continue to apply to existing and previously started postings. In plain terms: assignments that begin before the switchover keep their current treatment, and assignments that begin after it fall under the new regime. That single distinction is what makes the next two years an audit window, not a waiting room.

What Article 12 actually decides

Article 12 of the Coordination Regulation is the provision that lets a posted worker stay in their home country’s social security system for a limited period while working in another EU state. It is the reason the A1 certificate exists. Without Article 12, the default rule applies: you pay contributions where you physically work. With Article 12, and the right paperwork, you keep contributing at home. The revision does not scrap this logic, it tightens the conditions around duration, chaining of consecutive postings, and continuity of healthcare cover.

One stated aim of the revision, according to the reporting on the Parliament vote, is to simplify and speed up social security administration. In practice, member-state authorities have spent years disputing whether a given posting genuinely qualified for A1 treatment or whether it was a de facto local employment relationship. The new text is meant to reduce that ambiguity, though the finer detail of the tightened conditions only takes effect in 2028.

For employees on posting: what changes for you

If you are currently on assignment in another EU country, or your posting starts before July 2028, the old A1 regime still governs your situation. Your contributions continue to flow to your home country, your pension accruals continue there, and your healthcare cover follows the arrangement your employer already set up.

If your posting is being planned for after July 2028, or if it might be extended or chained onto another posting past that date, three practical questions are worth raising with your HR or mobility contact now:

• Which country will collect my social contributions for the full duration of this assignment, including any extensions?
• Which country will my pension accrue in, and how does that affect my future entitlements?
• How is my healthcare cover handled if I move between countries during the assignment, and does that change after July 2028?

These are not exotic questions. They are the ones that determine whether a nominal pay rise on a foreign posting actually leaves you better off after contributions and long-term pension impact are counted in. The two-year transition is exactly the moment to ask them, because the answers will differ depending on which side of the July 2028 line your assignment falls.

For HR and mobility teams: the audit window

For HR, legal, and global-mobility functions inside multinationals and staffing agencies, the twenty-four-month transition is the substantive story. It creates a filing and compliance window in which every current and planned cross-border assignment needs to be sorted into one of two buckets: postings that grandfather under the old A1 regime, and postings that trigger the new Article 12 obligations.

A working audit starts with three questions applied to every assignment on the books:

• Start date and expected end date. Anything scheduled to end before July 2028 sits cleanly inside the transitional provision. Anything scheduled to run past it, or likely to be extended past it, is a case to model under both regimes.
• Chaining risk. Postings that follow each other in short succession, sometimes across different worker categories, have been the flashpoint in past disputes with member-state authorities. Mapping which of your current assignments belong to a chain, and how the chain reads under the new duration rules, is the highest-value line item in this audit.
• Healthcare continuity. Cross-border assignments often rely on ad-hoc arrangements to keep the worker covered in the host country. The revised text is meant to clarify continuity obligations. Where your current setup depends on informal understanding rather than documented provision, the transition is the moment to formalise it.

Staffing agencies with high volumes of short cross-border placements face the sharpest exposure. The old regime tolerated a fair amount of variation in how member states interpreted duration and chaining; the new text signals a narrower band. Waiting until 2028 to reclassify assignments means doing the reclassification without the transitional cover that the old rules still provide today.

Why acting now beats waiting

A two-year transition sounds generous. In practice, cross-border assignments are often planned twelve to eighteen months in advance, extension decisions are taken six to nine months before end date, and the paperwork trail for a disputed A1 case can run for years. The effective window for auditing existing postings and shaping new ones so they land on the intended side of the July 2028 line is narrower than the calendar suggests.

There is also a practical asymmetry. If an assignment ends up on the old side of the line and the old rules turn out to be more favourable, nothing needs undoing. If it ends up on the new side without deliberate design, unpicking it after the fact means renegotiating contributions, contracts, and sometimes the assignment itself, with a member-state authority already applying the new text.

What to do in the next quarter

For employees, the immediate step is a short conversation with HR about which regime your current or planned posting falls under, and how it affects contributions, pension accrual, and healthcare. Ask for it in writing. If your assignment straddles the July 2028 date, ask specifically what changes at that point.

For HR and mobility leaders, the immediate step is inventory: every active and planned posting mapped against the July 2028 line, with chaining and healthcare exposures flagged. That inventory is what turns a two-year transition from a compliance risk into a design opportunity, one that lets you place each assignment on the side of the line that actually fits its purpose.

The regulation itself does most of its work in 2028. The decisions that determine how it lands in your organisation are taken well before then.