Russia’s central bank sold $420 million of foreign currency in its third day of interventions this month to slow the ruble’s world-beating decline.

The monetary authority spent the funds on Oct. 6 to shore up the ruble, according to the latest data on its website. The bank also said it shifted the upper boundary of the currency’s trading band by 5 kopeks yesterday, a move that may have taken its spending to $2 billion in the past three trading days. The exchange rate was little changed at 44.7546 versus the dollar-euro basket as of 12:01 p.m. in Moscow today.

The currency sales underscore the price President Vladimir Putin is paying for his country’s annexation of Crimea and alleged support for rebels in eastern Ukraine. The U.S. and Europe have imposed sanctions on Russian individuals and companies that have curbed access to overseas financing and fueled an exodus of foreign capital. Oil fell for a second day.

“The declining oil price and local demand for foreign currency force the central bank to intervene and move the band,” Dmitry Polevoy, chief economist for Russia at ING Groep NV in Moscow, said in an e-mailed note. “Only the tax period can alleviate this tension.”

The Bank of Russia will probably need to spend as much as $30 billion by year-end to slow the decline in the ruble, which lost 14 percent against the dollar last quarter, according to UralSib Capital. Crude oil, which brings Russia half of its state budget revenue along with natural gas, fell 1.5 percent to $90.76 per barrel in London, the lowest in more than two years.

Reserves Drop

The nation’s reserves have fallen by the equivalent of $55 billion in 2014 to a four-year low of $456.8 billion last week, poised for the biggest annual depletion since 2008, when the cash pile slid $160 billion from an August peak through year-end amid central bank efforts to stem the ruble’s drop.

Demand for dollars and euros is growing among Russian companies as they contend with $54.7 billion of debt repayments in the next three months, according to central bank data. Local tax payments in the second half of the month can support the ruble as exporters convert their foreign-currency revenue.

Retreating oil prices and U.S. and European Union sanctions that have shut Russian companies out of international financial markets are prompting Central bank Governor Elvira Nabiullina to spend the nation’s reserves, even as she seeks to move to a freely floated ruble by the start of 2015.

When the currency crosses the upper trading band, the central bank sells $350 million before shifting the boundary by 5 kopeks, according to official guidelines. Russia spent $40 billion in the currency market this year through May, excluding the latest interventions.

The rate on a three-year cross-currency basis swap between the Russian and U.S. currencies reached negative 290 basis points, the most since at least 2006, according to data compiled by Bloomberg. A negative rate signals traders are willing to pay a premium to obtain dollar cash flows for rubles.

Bloomberg