Highlights – LSE:ZEN

• Zenith says ICSID has again asked Tunisia to pay its outstanding share of arbitration costs.

• The company states Tunisia has paid none of the procedural costs normally split equally between both parties.

• Zenith's UK subsidiaries pursue an approximately US$573m claim against Tunisia under the 1989 UK–Tunisia Investment treaty.

• An earlier update estimated the tribunal's award for the first quarter of 2027, following an April 2026 merits hearing.

Arbitration is meant to share the bill. Zenith Energy (LSE: ZEN) says that has not happened in its treaty dispute with Tunisia. In an update issued on 9 November 2026, the London-listed energy producer said the International Centre for Settlement of Investment Disputes (ICSID) had once again asked the Republic of Tunisia to pay its outstanding share of the arbitration costs, and that its own subsidiaries have carried those costs so far.

What Zenith disclosed

The claim is brought by Zenith's UK subsidiaries, referred to as the Claimants, under the 1989 bilateral investment treaty between the UK and Tunisia. It is valued at approximately US$573m.

According to the release, Tunisia "has failed to contribute towards any of the procedural costs ordinarily shared equally between the parties" since the arbitration began. The Claimants have therefore borne those expenses.

The company did not hold back on tone. It described the refusal as "a deliberate, bad-faith attempt to obstruct the administration of justice", and the Claimants called it part of an "ongoing pattern of procedural abuse". These are Zenith's own characterisations rather than findings by ICSID or the tribunal.

The release also notes that Tunisia is represented by the law firm Curtis, Mallet-Prevost, Colt & Mosle LLP.

How the dispute reached this point

The case stems from alleged obstructions linked to Zenith's Tunisian production concessions, Sidi El Kilani and Ezzaouia, including the processing of oil sales. Zenith first announced the ICSID arbitration in June 2023, bringing the claim under Article 8 of that treaty.

By late June 2026, the process had reached its final post-hearing phase. A merits hearing took place in April 2026, post-hearing briefs were due by 31 July and 30 September, and the tribunal's award was estimated for the first quarter of 2027. That same June update said Tunisia had formally recognised a Zenith subsidiary's ownership of about 3,987 barrels of Crude Oil produced from the concessions.

Zenith has run a separate track too. In December 2024 it reported a positive result in its ICC-1 arbitration against ETAP, Tunisia's national oil company, with an award of about US$9.7m.

Why the cost row matters

For a company of Zenith's size, carrying the full administrative cost of a long investment-treaty case is a real cash call. Monday's release did not state the amount Tunisia owes, any payment deadline ICSID may have set, or the date of ICSID's latest request.

The update does not change the size of the claim, and no award has been issued. The release refers to the case moving towards a final award, which keeps Q1 2027 as the most recent timing estimate on record.

Risks investors may weigh

Arbitration outcomes are uncertain, and a favourable award would not by itself guarantee collection from a sovereign state. Unpaid procedural costs can also lengthen disputes if they disrupt how a case is administered. Zenith's description of bad faith is an allegation, and Tunisia's position is not set out in the release.

Signposts for Zenith shareholders

The company says it "will provide further updates as appropriate". Key markers include any ICSID response to non-payment, confirmation of the award timetable and, eventually, the tribunal's decision on the merits.

A courtroom story with a cash angle

Zenith is listed on the Main Market of the London Stock Exchange, on Euronext Growth Oslo and on Sweden's Spotlight Stock Market. Among small-cap energy names on the UK stock market, its Tunisian claim remains one of the larger contingent items in play, and Monday's update puts the spotlight on who is paying to pursue it.