Yuganskneftegaz pumping station, formerly owned by Russian oil giant Yukos, in Priobskoe oilfield in 2007. It’s not clear whether Russia will have to pay Yukos’s former shareholders $50 billion for dissolving the company. (EPA/Yuri Kochetkov)

In 2014, an international tribunal decided Russia had unlawfully expropriated the Yukos oil company — and owed $50 billion to Yukos shareholders. Last week, a Dutch court found that, no, Russia doesn’t have to pay.

Here’s the big catch: International investment law is so complicated that Russia might have to pay anyway.

Russia is experiencing the ins and outs of the controversial Investor-State Dispute Settlement (ISDS) system. ISDS allows foreign investors to sue states for compensation in international tribunals should the investor feel the state failed to protect the investor’s property rights. It is the controversial provision found in NAFTA, the Trans-Pacific Partnership (TPP), and thousands of other treaties.

What happened to Yukos, and what does it mean for future investor-state disputes? 

What’s the Yukos saga?

In 2014, Russia was found liable for an unprecedented $50 billion in awards to the shareholders of Yukos, the oil giant that Russian President Vladimir Putin dismembered in 2003. The former CEO of Yukos, Mikhail Khodorkovsky — a funder of opposition parties and possible challenger to Putin — spent 10 years in a Siberian jail for fraud and tax evasion.

But Yukos traced its ownership to the Isle of Man (a British Crown dependency) and Cyprus — both of which are, basically, tax havens. So former Yukos shareholders applied to use ISDS, because the U.K. and Cyprus are signatories to the Energy Charter Treaty that enables ISDS. Russia signed but never ratified the Energy Charter Treaty, so a three-person international tribunal had to decide whether Yukos shareholders could sue Russia anyway.

The tribunal said yes, and the $50 billion in awards came down. The tribunal reasoned that signatories are obligated to abide by the treaty provisionally, pending ratification. Putin immediately said Russia wouldn’t pay – and took a lot of flak from international business.

How to make Russia pay? Take what you can, where you can.

Since then, Yukos shareholders have been using their rights under international law to seize Russian state assets outside of Russia. Attempts are ongoing in Belgium, France, the United States, Germany and the U.K. Assets owned by the Russian government but not subject to sovereign immunity protections are up for grabs. For example, earnings by Russian state-owned enterprises that are held abroad are vulnerable, but Central Bank holdings abroad are not. A particularly interesting situation arose last year when former Yukos shareholders tried to claim the contents of a cosmonaut exhibit at the London Science Museum. Russia “sold” the artifacts to the museum and is “buying” them back to avoid seizure.

The Dutch court’s ruling last week adds another twist. Effectively, the Dutch court said, no, Russia never ratified the Energy Charter Treaty (which conflicted with Russian law in any case), so the original tribunal had no jurisdiction and the $50 billion is off the table.

But don’t be tricked by news reports. It is far from clear that the Dutch ruling (and any possible Dutch appeal) is binding on courts in other countries. Lawyers for the Yukos shareholders point out that there is no ISDS appeals process, so there is no mechanism to overturn the original $50 billion award. International investment law is so decentralized that it isn’t clear what one domestic court’s interpretation of the law means for domestic courts in other countries.

As a result, former Yukos shareholders can keep trying to get the original $50 billion award enforced in countries other than the Netherlands. Will they be successful? It would certainly be difficult and costly, but it isn’t impossible. In all likelihood, Russia will have to keep fighting — or pay up.

What can we learn from all this?

States usually pay their awards, so Russia’s pushback — and success (in the Netherlands at least) — is notable. Of the 461 public ISDS arbitrations that reached a conclusion from 1990-2014, foreign investors have won awards in 29 percent of the cases (and 33 percent settled before a final ruling was reached). In the vast majority of cases where foreign investors won an award, they haven’t complained about their ability to collect their awards from the state. By my count, states have tried to leverage international law to avoid paying in just 40 or so public instances (including the three Yukos arbitrations).

ISDS isn’t just about rich multinational corporations suing poor countries. Russian multinational corporations have won awards from other states six times, settled three times, and lost only once, with several arbitrations pending. Russia represents an important category of states: middle-income and developing countries that get sued but also have multinational corporations that do the suing. This crossover might breathe new life into ISDS.

Rachel Wellhausen is assistant professor of government at the University of Texas at Austin and author of the book “The Shield of Nationality: When Governments Break Contracts with Foreign Firms.”