The board of Russia-based Norilsk Nickel, the world's largest nickel and palladium producer, approved on Tuesday a public buyback of its shares at $306 per ordinary share and $30.6 per ADR.

The offer came after the board of the world's top aluminium producer, UC RUSAL, rejected last week the $8.75 billion buyback offer, at the same price.

Norilsk said in a statement it has offered the buyback to other shareholders, using cash totalling up $4.5 billion, which would allow it to acquire 7.71 percent of the company.