Russia's dominant lender Sberbank said on Friday it would pay 3 billion roubles ($31.63 million) to the state budget as its contribution to a one-off windfall tax Moscow is levying on companies' excess profits.

President Vladimir Putin signed the tax into law this month. It is aimed at raising 300 billion roubles and easing strain on the state budget as Russia wages its war in Ukraine.

Reuters reported exclusively this month that Russia had doubled its 2023 defence spending target to more than $100 billion, or a third of all public expenditure.

The windfall tax rate will be 10% of the difference between firms' average profit for 2021-22 and their profit for 2018-19. Firms can get a 50% discount if they pay before Nov. 30. ($1 = 94.8525 roubles) (Reporting by Alexander Marrow Editing by Gareth Jones)