Later this year, three arbitrators will begin to consider the largest compensation claim ever launched outside the normal court process. At face value, it is worth $32 billion. According to the claimants, though, not even that eye-watering sum would be enough to cover their losses. The figure they may eventually be seeking could be more than $100 billion.

At the heart of this fascinating tale is Russia’s attempt to open its oil industry to Western investment in the 1990s, followed a decade later by President Putin’s decision to bring his country’s energy resources back under state control. The claimants are investors who lost money in Yukos, the now-bankrupt oil company formerly run by Mikhail Khodorkovsky. Convicted of fraud in what was widely seen as a politically motivated prosecution, Mr. Khodorkovsky received an eight-year prison sentence in 2005 and was sent to Siberia. He would have been eligible for parole by now if the Russian authorities had not brought further charges of embezzlement against him last year. And the defendant? No less than Russia itself. Yukos shareholders accuse the Russian Federation of unlawfully expropriating their investments in what had been Russia’s largest oil company.