Government is discussing with big business a one-time voluntary contribution to the budget, said First Deputy Prime Minister Andrei Belousov. He noted that in tax practice there is such a concept as windfall tax - a one-time collection of taxes on unforeseen profits, stressing that it is seen as a "voluntary story" exclusively for big business. He did not name the amount of the contribution. However, media sources said that the state wants to receive from businesses ₽200-250 billion.