LONDON (Reuters) - Last week's truce between BP (BP.L) and its oligarch partners in Russia has not settled the row for good, and the British oil company could yet have to pay more for its new Russian tie-up with Kremlin-backed Rosneft.
On Friday, BP agreed to execute its planned Arctic exploration venture with Rosneft through its half-owned TNK-BP TNBP.MM venture, rather than directly.
The deal comes after Alfa-Access-Renova (AAR), the consortium of four billionaires which owns the other half, complained that the Rosneft deal breaches a shareholder agreement giving them exclusive rights to BP's exploits in Russia.
Rosneft's consent is required if the oligarchs, Mikhail Fridman, German Khan, Viktor Vekselberg and Len Blavatnik, are to be allowed to take their seats at the Arctic exploration table that is at the center of the BP-Rosneft tie-up.
If Rosneft agrees to a plan it has previously said it is opposed to -- BP can proceed with a planned $16 billion share swap with Rosneft which was agreed as part of the Arctic exploration plan.
BP investors were cheered by the apparent end of the spat, and BP shares, which have lagged rivals by around 10 percent since the Rosneft tie-up was first announced, rose 3 percent on the news on Friday, holding onto those gains on Monday.
However, continued uncertainty is preventing a more meaningful recovery in BP's shares, which are also weighed down by guesswork over the final bill it will face for last year's Gulf of Mexico oil spill.
One key worry is whether Rosneft may now want to renegotiate the terms of the share swap part of the deal. Shifting valuations since the agreement was announced in January would give them good cause.
The deal swapped a 5 percent BP stake for a 9.5 percent stake in Rosneft, with each valued at $7.8 billion, using January 14 prices.
By this week, the value of a 5 percent stake in the London-based oil giant was worth only $7 billion, while the value of a 9.5 percent stake in Rosneft had climbed to $8.5 billion.
"The question is whether Rosneft will try to revise the conditions of their relationship with BP," said Kaha Kiknavelidze, fund manager at Rioni Capital.
The peace deal with AAR has taken some heat off Chief Executive Bob Dudley, who unveiled the original tie-up with great fanfare.
However, even if Rosneft agrees to go along with Friday's agreement between AAR and BP, analysts do not believe it will represent the end to the regular spats that pop up between BP and AAR.
"This deal does not solve the longer-term issues on TNK-BP's shareholder structure," analysts at Credit Suisse said in a research note.
"We still think a change in shareholder structure at TNK-BP will eventually happen in some shape or form - possibly through a secondary IPO," the investment bank added. Investors like the idea of BP gaining access to Arctic exploration blocks which Rosneft said could contain as much oil as the North Sea did.
But they remain uncertain about the future of the plan, which BP had hoped would open a new and brighter chapter after the oil spill.
"It looks like the Russian outcome may be a little better than some commentators' worst-case fears, although BP will now be sharing the benefit of the Arctic exploration... rather than getting 100 percent of the opportunity," Martin Cholwill, equities manager at Royal London Asset Management told Reuters.
"The whole episode highlights the risks involved in doing business in Russia," he added.
TNK-BP has no offshore expertise and consequently, BP could have to inject its employees and technology into its Russian joint venture to make TNK-BP a suitable partner.
In 2008, the cost to TNK-BP of seconded BP workers was part of a dispute between BP and AAR, that investors feared could cost BP its stake in the venture. The complex nature of the remedy agreed last week frightens some investors.
"The question is how stable is the solution going to be. A lot of people are in the same bed," said one fund manager who declined to be named.
(Editing by Andrew Callus)