Weiss Asset Management has sold its 29.12% stake in Cadogan Petroleum to Shon Invest SA.The fully listed oil and gas company says that Shon Invest agrees with the strategy of developing the Ukrainian oil and gas assets. Cadogan had delayed its AGM because it asked the Takeover Panel to investigate the relationship of Weiss and another shareholder so that the Panel could rule whether it was a concert party trying to gain control of the board. Weiss wanted John Chapman, Eitan Milgram and Stephen Coe appointed as directors. Chapman would have become non-executive chairman. Milgram is employed by Weiss, which also wanted Ian Baron and Nicholas Corby to step down from the board. These proposals have been withdrawn from the AGM on 30 June.Weiss wanted Cadogan to focus on resolving litigation with former management and suppliers, collecting up to $38.5m owed by Global Processing Systems LLC and realising value from Ukrainian assets. It also wanted costs reduced.On 4 June, Cadogan said that it had received a potential offer of 16p a share for 51% of its shares. The selling shareholders would be given the chance to receive additional payments based on 50% of any net amounts received from a legal settlement with Global Processing Systems LLC. There has been no further news of the offerCadogan floated on the Main Market at 230p a share in June 2008 and has lost more than 90% of its value since then.