BP will find out this morning whether it can go ahead with controversial plans for a $10bn (£6bn) tie-up with Russia's Rosneft.
Arbitration judges in London have been considering a complaint from BP's partners in Russian joint venture TNK-BP since Monday.
The tribunal has already upheld claims from the Alfa-Access-Renova (AAR) consortium, which owns half of TNK-BP, that BP's plans for an Arctic exploration programme with Rosneft violate the TNK-BP shareholder agreement.
BP still wants to press ahead with the Rosneft share-swap but AAR says even that contravenes TNK-BP rules that all Russian activities be done through the joint venture. BP is understood to have requested a meeting with AAR's four billionaire oligarchs next week, to discuss the outcome of the tribunal whichever way it goes.
Separately, BP faces a pasting from church investors at next week's annual general meeting over the Gulf of Mexico disaster that killed 11 people and unleashed the largest oil spill in history last year.
Church investor groups in the UK and US are recommending members vote against the reappointment of Sir William Castell, the non-executive director who chairs BP's safety committee. "It's a way to express our unhappiness about BP's safety record," said Bill Seddon, the vice chairman of Britain's Church Investors Group.
Plans for a censorious shareholder resolution have been put off for a year to give BP boss Bob Dudley a chance to improve the company's safety culture. "We will give him a year to show us what has actually been done," Mr Seddon said.
UK and US church investors are also expected to vote against BP's remuneration report, in an ongoing complaint over executive pay.