What is an early signal of an investment treaty dispute?
An early signal is a public government act that reduces the value or security of a foreign investment, in a way an investment treaty protects against. It comes before any notice of dispute is served. In 2025, 58% of the new cases registered at the International Centre for Settlement of Investment Disputes (ICSID) rested on a bilateral investment treaty (BIT), on ICSID's own count.
The protections most often engaged are fair and equitable treatment (FET) and protection against expropriation, both covered in our guide to investment treaty arbitration.
Measure to claim follows roughly the same sequence each time. A government measure harms the investment, the investor objects informally, then serves a notice of dispute, often called a trigger letter. A cooling-off period follows, and only then can the investor file a request for arbitration. The early signal is the first step in that chain, and a monitoring workflow tries to catch it there.
Which government measures most often turn into treaty claims?
Four kinds of measure account for most claims: licence revocations, new or retroactive taxes, tariff or contract changes, and expropriation.
Licence revocation is the most direct route. Tanzania's Mining (Mineral Rights) Regulations 2018 cancelled retention licences, including the Ntaka Hill nickel project, on 10 January 2018. Nachingwea v. Tanzania (ICSID Case No. ARB/20/38, UK-Tanzania BIT) followed, and the tribunal awarded about US$76.7 million in damages plus costs.
A tax can work the same way. Mongolia taxed gold sales above US$500 an ounce at 68% under a 2006 law, and that single provision produced Paushok v. Mongolia, brought under the Russia-Mongolia BIT and decided under UNCITRAL rules; the tribunal's award on jurisdiction and liability came down on 28 April 2011.
Tariff changes are common too. Spain's Royal Decree-Law 9/2013, enacted 12 July 2013, removed the fixed feed-in tariff for renewables, and dozens of Energy Charter Treaty claims followed, including Eiser v. Spain. Expropriation is the odd one out. Direct seizure of an asset is rare; most claims instead allege creeping expropriation, a run of smaller measures that add up to the same result. But that line is not always clean, and tribunals do not read it the same way twice.
How much time passes between the measure and the claim?
Usually months, sometimes years. Eiser v. Spain (ICSID Case No. ARB/13/36) was registered five months after Spain's Royal Decree-Law 9/2013 took effect; ICSID's registration record puts the date at 23 December 2013. Nachingwea v. Tanzania (ICSID Case No. ARB/20/38) took roughly two years to reach ICSID after Tanzania's 2018 licence revocation. The gap is not always months, however: sometimes the first signal is a draft law that never passes, and nothing follows it at all.
Most of that gap is procedural: paperwork and treaty-mandated waiting periods, not investor hesitation. Roughly 90% of bilateral investment treaties carry a cooling-off clause, and six months after a written notice of dispute is the usual term. Some treaties set three to five months; a few run longer.
The Netherlands Model BIT (2019) does the same in Article 19, but counts the six months from the written request for consultations (an ICSID Review article works through it). So the outreach window opens the day the measure is published and stays open through the whole cooling-off period.
Where do early signals appear first?
Early signals surface first in the host state's own publications. The official gazette records the measure the day it takes effect. Tanzania's Mining (Mineral Rights) Regulations 2018, the instrument behind the Nachingwea claim, cancelled the Ntaka Hill licence on 10 January 2018. The responsible ministry or regulator often issues its own announcement too, and a sector register such as a mining cadastre updates licence status directly.
In our experience the cadastre is the one people forget. Local-language press in the country concerned typically reports the story before any English-language outlet does.
A second layer comes from the investor's side. A listed company must disclose a material licence change to its stock exchange, although that only helps when the investor is listed. Many mining and infrastructure investors are private. Trade press covering sectors such as oil and gas often follows within days, mostly not in English. None of it reaches arbitration news, which reports a case only once it is registered. Our guide to real-time monitoring of investment disputes covers how teams track these sources.
Why does speed matter for a law firm's business development?
Speed matters because the investor chooses counsel in the weeks after the measure, while deciding whether to send a notice of dispute. It rarely switches counsel afterwards. The firm that reaches the investor first, with a treaty analysis ready, shapes how that first conversation goes. By the time a case is registered at ICSID, the mandate has usually gone to someone else.
The numbers back this up. ICSID registered 63 new cases in 2025, its second-highest year on record, most of them in mining, oil and gas and construction. Where that concentration sits by country is in our piece on ICSID caseload trends for 2026.
What this means for practice
Treat dispute identification as a daily monitoring task, not a question asked at intake. Gazettes, ministry announcements and local press should be read every day across the countries and sectors a practice covers. A team is doing this well when it sees more notices of dispute coming before they are served.
Monitoring tools such as DSPT Finder read these sources in 32 languages across more than 159 countries. They surface the new government actions and freshly served notices of dispute that matter, so a business development team can act before the request for arbitration is filed.
For more on this topic, see our guide to AI-based regulatory risk assessment and the fair and equitable treatment standard.
Frequently asked questions
What counts as an early signal of an investment treaty dispute?
A public government act that harms a foreign investment in a way a treaty protects against: a revoked licence, a new tax aimed at a sector, a cut to a guaranteed tariff, or a seizure of assets, before any notice of dispute is served.
How long is the cooling-off period before an investor can file for arbitration?
Most bilateral investment treaties, about 90%, require a waiting period after a written notice of dispute. Six months is the most common length. Some treaties use three to five months; others run to 12 or 18 months.
What is a notice of dispute, and what does it start?
A written letter from the investor to the host state stating that a treaty dispute exists. Also called a trigger letter or notice of intent, it starts the cooling-off period and is often the last step before a request for arbitration.
Which sectors saw the most new ICSID cases in 2025?
ICSID's Caseload Statistics, Issue 2026-1, put mining first among the 63 new cases registered in 2025, at 24%, with oil and gas second at 21% and construction third at 16%.
How can a law firm monitor for investment treaty disputes before they are filed?
By watching the sources where measures first appear: official gazettes, ministry and regulator announcements, mining cadastres, exchange filings and local-language press across the countries a practice covers. Read them every day with the relevant treaty protections in mind.