How many of the negotiating chapters required to join the EU will Montenegro have closed at the end of 2026?

TL;DR

I forecast 30 chapters as the most likely year-end total. The distribution has a mean of 29.1, a central 80% interval of 25–33, and a 12% chance that all 33 close. The short-run pipeline drives more closures, but Croatia and Chapters 23, 24, and 27 keep a clean sweep out of the base case.

Context

At the forecast cutoff, the Council of the EU reported 18 of 33 chapters provisionally closed. The client’s count of 14 was accurate after the 17 March 2026 closure of Chapter 21, but Chapters 2 and 28 closed on 15 June 2026 and Chapters 8 and 29 on 14 July 2026. Fifteen chapters remain.

The resolution standard is strict. Technical readiness and draft Council positions do not count. A chapter must be formally provisionally closed at an accession conference, and member states may revisit a provisional closure before the overall agreement is complete, as the Commission’s accession-process description explains.

Evidence

The historical backbone is Montenegro’s full chapter-closing record. It contains ten closing events from December 2012 through July 2026:

For most of the process, closures were rare. The pace changed after the June 2024 rule-of-law milestone: Montenegro closed 15 chapters between December 2024 and July 2026. The closest completed analogue is Croatia, which had closed 28 of 35 chapters by the end of 2010 and completed its final seven when negotiations ended in June 2011. Montenegro needs 15 closures in roughly four effective months, a much more compressed sprint.

The strongest short-run signal is the Council working-party page for 1 September 2026, which publicly lists draft common positions for Chapters 12, 18, and 19. Montenegro’s public broadcaster reported that Chapter 14 would also be discussed. But the official COREPER summary record says the Chapter 14 item was withdrawn on 10 July, and the subsequent accession conference closed only Chapters 8 and 29. I assign Chapters 12, 18, and 19 about a 96–97% year-end chance, but Chapter 14 only 60%. (data.consilium.europa.eu)

The institutional signals are strong. The Council created an ad hoc group to draft Montenegro’s accession treaty on 22 April 2026. Ireland’s prime minister said on 7 July 2026 that the presidency would aim to complete the negotiations, while the Commission’s 30 June financial package advances Chapter 33. The presidency calendar contains formal General Affairs Council windows on 22 September, 13 October, 19 November, and 15 December. That is enough calendar space for several batches, though the presidency cannot override a national veto.

Montenegro has also converted several benchmarks into concrete acts. Parliament filled the two remaining Constitutional Court vacancies on 16 July, adopted a central-bank independence amendment on 24 August, and approved full visa-policy alignment effective 1 November. Legislation tied to the final Chapter 15 benchmark and new Chapter 27 environmental-management measures add to the positive case.

The counterweight is implementation. The Commission’s 17 July 2026 rule-of-law report still found gaps in judicial staffing, infrastructure, efficiency, anti-corruption enforcement, and institutional capacity. The comprehensive 2025 enlargement report, covering 1 September 2024 through 1 September 2025, rated Chapter 27 and Chapter 33 at only some level of preparation, while Chapters 23 and 24 required further implementation. Its vintage is old, but it remains the latest systematic chapter-by-chapter baseline.

Croatia is the clearest political obstacle. Its foreign ministry’s 22 July statement demanded action on wartime compensation, missing persons, war crimes, property claims, the Morinj memorial, the maritime boundary, and the training ship Jadran. Chapter 31 is technically advanced under the 2025 Commission report, but politically it is the least likely remaining closure in my model, at 36%.

I modelled the 15 remaining chapters in the order 1, 9, 12, 14, 15, 16, 17, 18, 19, 22, 23, 24, 27, 31, and 33. I used five shared regimes: 4% disruption, 18% limited delivery, 42% strong baseline progress, 25% accelerated closeout, and 11% coordinated full-package completion. Within each regime, each chapter has a closure probability, and an exact Poisson-binomial calculation produces the number closed. Mixing regimes captures the positive correlation created by batch conferences and common political decisions. The resulting mode is 30, the mean is 29.1, the probability of at least 30 is 48.8%, and the probability of 33 is 12%.

What's non-obvious

The Chapter 14 paperwork is easy to misread. The annex to the COREPER record lists its common position under approval, but the record’s opening paragraph says item 88c was not approved; it was withdrawn. The official September working-party page then lists only Chapters 12, 18, and 19. This is stronger evidence of a live veto than the usual claims that Chapter 14 is technically ready. (data.consilium.europa.eu)

Treaty drafting is a real positive signal, but it is not a closure decision. I read it as proof that the EU is spending administrative and political capital on Montenegro, not proof that all remaining benchmarks are met. The strict 2026 deadline is also softer than it looks: Commissioner Marta Kos said after the 14 July conference that 2028 membership could remain possible even if every chapter did not close this year. That lowers the cost of letting a few hard chapters slip into early 2027.

Uncertainties

Public Council records reveal only part of the pipeline. I could not verify draft common positions for most of the 11 chapters outside the immediate September group and Chapter 14. Some preparatory documents are restricted, so the lack of a public document is not evidence that no work is occurring.

The next full Commission enlargement report was not available by the cutoff. The July rule-of-law report predates the late-July and August reforms, while Montenegro–Croatia talks are mostly private and could produce a rapid package deal. The reported accelerated EU plan relies on unnamed Commission sources, and exact dates for the remaining accession conferences have not been announced. Those gaps drive the broad upper tail and the 4% disruption regime.