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

TL;DR

My forecast is a median of 28 provisionally closed chapters and a mean of 27.5 by 23:59 CET on 31 December 2026. Montenegro has 16 chapters closed after the 15 June 2026 accession conference, and the EU has begun work on its accession treaty, so a strong second-half push is likely (Council, 15 Jun 2026). I put 14% on all 33 chapters being closed because that requires clearing the rule-of-law, environment, food-safety, budget, competition, and Croatia-sensitive foreign-policy files in one six-month sprint.

Context

Montenegro is the most advanced current EU candidate in the old chapter-based process. It opened accession talks in June 2012, has opened all 33 negotiating chapters, and had 16 chapters provisionally closed after chapters 2 and 28 closed at the 27th Accession Conference on 15 June 2026 (Council Montenegro page, last review 15 Jun 2026; Council, 15 Jun 2026).

The key break came on 26 June 2024, when the EU confirmed that Montenegro had overall met the interim benchmarks for chapters 23 and 24, which allowed the closing phase to restart after years of near-stasis (Council, 26 Jun 2024). The question is now timing: whether 17 remaining chapters can be formally provisionally closed before the exact 31 December 2026 cutoff.

Evidence

The historical record is lumpy. The unit in the table is provisionally closed chapters; the coverage window is 18 December 2012 to 15 June 2026; the sample is 9 closure events and 16 total closures; the latest official count vintage is the Council release of 15 June 2026 (Council, 15 Jun 2026).

The base rate alone is too low. Montenegro closed only 3 chapters from December 2012 through June 2024, then closed 13 more from December 2024 through June 2026 after the chapter 23 and 24 interim-benchmark milestone (Council, 26 Jun 2024; Council, 15 Jun 2026). Still, the needed pace is extreme: Montenegro must close 17 more chapters in the second half of 2026, compared with 4 closures in the first half of 2026 and 10 closures in the roughly 12 months from 27 June 2025 to 15 June 2026 (Council, 27 Jun 2025; Council, 15 Jun 2026).

The closest accession reference class is Croatia, but it argues for a final sprint rather than for assuming all 17 chapters close. Croatia had seven chapters left in December 2010 and closed its last four chapters on 30 June 2011, so endgame bundling is possible; Montenegro has 17 left at the comparable stage, more than double Croatia's final backlog (EUinside, 23 Dec 2010; Tportal, 30 Jun 2011).

The upside case is stronger than a simple trend model. The Commission's 2025 enlargement package said Montenegro was on track to close accession negotiations by the end of 2026 if reform pace was maintained (European Commission, 4 Nov 2025). Montenegro's 2026–2027 accession programme was explicitly framed as a roadmap to close all chapters by end-2026 and listed 495 planned acts in 2026, including 67 strategic documents, 119 laws, and 309 by-laws (Montenegro Ministry of European Affairs, 31 Jan 2026). Ireland holds the Council presidency in July–December 2026, and Ireland's European affairs minister said Ireland wants to facilitate Montenegro's goal of closing all negotiating chapters by end-2026 (Council presidency page; Government of Ireland, 17 Mar 2026).

The EU-side signal is also real. The Council said on 15 June 2026 that the Ad Hoc Working Party for drafting Montenegro's accession treaty had been established during the Cyprus presidency, and the Commission released €44.2 million to Montenegro under the Reform and Growth Facility on 20 May 2026 after a positive assessment of implemented reform steps (Council, 15 Jun 2026; European Commission, 20 May 2026). I read this as evidence that Brussels is preparing for accession, not just praising reforms.

The downside is the composition of the remaining chapters. After the June 2026 closures, the open set is 1, 8, 9, 12, 14, 15, 16, 17, 18, 19, 22, 23, 24, 27, 29, 31, and 33, inferred from the official 33-chapter count and the closure history above (Council, 15 Jun 2026; Commission state-of-play PDF, updated 30 Jun 2020). The latest full Commission report, published on 4 November 2025 and covering 1 September 2024 to 1 September 2025, said Montenegro's institutions remained fragile, chapter 23 still needed stronger judicial and anti-corruption implementation, chapter 24 had limited progress and a visa-policy closing-benchmark issue, chapter 27 had only some level of preparation, chapter 12 made limited progress, chapter 8 still needed a credible enforcement track record, and chapter 33 had only some level of preparation (Montenegro Report 2025 PDF).

Two weak signals cut against a clean 33. On 12 June 2026, Montenegro's European affairs minister said constitutional amendments tied to judicial reform would not be adopted by the end-June deadline, costing Montenegro €4.6 million from the EU Growth Plan (Vijesti, 12 Jun 2026). Croatia blocked closure of chapter 31 in December 2024, and Montenegrin officials were still saying in June 2026 that they hoped to resolve most open issues with Croatia in the coming months (HRT, 16 Dec 2024; CE Report, 18 Jun 2026).

I modelled the outcome as correlated political scenarios, not as 17 independent chapter-level coin flips. The current count of 16 is the anchor; I leave 0.1% below 16 for the edge case that a provisionally closed chapter is revisited, since the Council says the EU may return to a provisionally closed chapter if necessary (Council, 15 Jun 2026). My distribution assigns 13% to ending at 16–22, 16% to 23–25, 34% to 26–29, 22% to 30–32, and 14% to 33. That gives a mean of 27.5, a median of 28, and a 36% chance of 30 or more.

What's non-obvious

The treaty-working-party signal matters more than most headlines. It means the EU is already preparing accession-law machinery before the final chapters are closed, which shifts the forecast well above a raw pace extrapolation from 2026 closures so far (Council, 15 Jun 2026). It does not mean 33 by 31 December is the central case, because treaty drafting can run alongside unfinished chapters and because transitional arrangements can be negotiated without every political objection disappearing by the resolution date.

The other missed point is that the last chapters are not a random half of the acquis. Chapters 23, 24, 27, 12, 8, 31, and 33 are exactly the files where implementation records, administrative capacity, money, and unanimity matter most (Montenegro Report 2025 PDF; Council enlargement explainer, last review 4 Nov 2025). A late political bargain could close almost all of them at once, which is why 33 gets real probability; a single unresolved rule-of-law or Croatia issue can also leave Montenegro stuck at 30–32.

Limitations

The main missing evidence is not public. Draft EU common positions, Coreper instructions, and member-state objections for the remaining chapters would matter more than most public speeches, but I could not verify a chapter-by-chapter H2 2026 schedule from official sources. The Commission's latest full chapter assessment was published on 4 November 2025 and covers the period ending 1 September 2025, so it may understate reforms passed in late 2025 and spring 2026, while Montenegro's government roadmap may overstate how fast adopted laws become implemented capacity (Montenegro Report 2025 PDF; Montenegro Ministry of European Affairs, 31 Jan 2026).

The largest irreducible uncertainty is unanimity. Enlargement decisions in the Council generally require unanimous agreement, and the accession treaty itself requires unanimous Council approval and ratification by all member states and the candidate country (Council enlargement explainer, last review 4 Nov 2025). That makes the final count sensitive to political bargaining that can move late and leave little public trace before an accession conference.