MOSCOW—The Bank of Russia moved again Tuesday to shore up the ruble, spending as much as $1.75 billion over the last three trading days in the heaviest interventions since mid-March.

The ruble has been hitting fresh lows almost daily since the beginning of October. Sliding oil prices have hit Russia’s economy hard, given the country’s dependence on energy exports. At the same time, sanctions imposed by Western countries over the Ukraine crisis have limited the ability of Russian banks and companies to borrow abroad.

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