Graham Stack in Kyiv -

Oleg Deripaska's En+ holding has offered a $9bn buyout of Rusal's 25% stake in Norilsk Nickel. Rusal's unhappy minority stakeholders will decide the response to the offer. On the one hand, it's an opportunity to defuse tension between Rusal's shareholders, but the value of the offer is likely to prove a stumbling block.

The offer comprises a $4.6bn Sberbank loan and $4.4bn in cash, according to Vedomosti. Whilst on the one hand it presents an opportunity for the shareholders to extricate Rusal from the never-ending vicious shareholder dispute at Norilsk, and could transform the heavily indebted company, on the other, the value of the offer is well below recent bids from Vladimir Potanin on the other side of the Norilsk squabble.

The spark for the offer is clearly the deteriorating relations amongst the oligarchs that own Rusal, following as it does the resignation of Viktor Vekselberg as chairman and a spiteful public exchange of accusations between him and the company in mid-March.

In turn, that is widely understood to have resulted from Rusal's refusal of more than one offer from Potanin last year, one of which tendered $12.8bn for a 20% stake, implying a value of $16.1bn for the full 25%. Motivated by Deripaska's very personal battle to gain control of Norilsk, the refusal clearly angered Vekselberg and fellow stakeholder Mikhail Prokhorov.

From that angle then, the $9bn Deripaska is now offering them to skedaddle is likely to rub salt in the wounds, whilst also provoking even greater concern over corporate governance in Hong Kong, where the aluminum giant listed in 2010. That said, whilst the stake is currently valued at $14.5bn according to a Rusal source, 25% of Norilsk shares would have cost just $8.7bn on the LSE on March 23.

"$9bn might not seem too appealing for Rusal's non-core shareholders, and they could try to push the price up," suggest analysts at Troika Dialog. "In the BoD decision [on the offer], the representatives of Rusal and En+ will not be able to vote, while each of Vekselberg, Prokhorov and Glencore will have a veto right, so their unanimous support is critical." Swiss-registered commodities trader Glencore - with just over 8% of Rusal shares - has shown itself to be a close ally of Deripaska.

However, despite the clear financial and personal slight, Vekselberg et al could also be tempted by other elements, with a deal likely to transform Rusal's financial situation say analysts. "The company could cut its net debt, which currently stands at $11 bln, and start paying dividends, much desired by non-core shareholders Viktor Vekselberg, Leonard Blavatnik and Mikhail Prokhorov," the Troika analysts continue. "Furthermore, the deal will isolate Rusal from the vicious corporate battle surrounding Norilsk Nickel. On balance the sale of the stake under the proposed terms would be transformational for Rusal and it appears to be the only solution to the current stalemate, so we hope that it will come to pass."

Others suggest the 40% premium turned down just a handful of months ago will stick in their throat however. " We believe Rusal minority strategic shareholders are unlikely to accept the transaction at a price that offers no premium to the market and no premium for control, especially taking into account Norilsk offers to Rusal made in 2011, which implied a substantial premium to the market and was effectively blocked by En+," write Alfa analysts.