The mystery surrounding the buyer of Yukos’s last big asset last week brought the curtain down on the dismantling of what was once the nation’s biggest oil major with a final bizarre flourish.

In a deal inside a deal, reminiscent of Russian matryoshki or “nesting” dolls, US businessman Stephen Lynch has laid claim to ownership of the former Rosneft unit, Promneftstroi, that won the final lot of Yukos assets. They went under the hammer last week for $305m, in a lot that included the oil major’s Dutch subsidiary Yukos Finance BV.