[AdmSmith]

The Russian foreign reserves that can be used is less than $200 bn

http://www.reuters.com/article/2014/12/18/us-russia-cenbank-reserves-idUSKBN0JW24J20141218

and they need a lot of money to save their banks and oil companies. According to this http://www.timesofisrael.com/russias-economy-could-collapse-in-months-says-financial-forecaster/

Russia will experience a total economic collapse within months.

[AdmSmith]

So Putin needs to find more dollars, and he needs to find them now. Where, you ask? Well, the answer is as obvious as it is unlikely: Russia’s companies. Now, the government has said it will never use capital controls—forbidding people and corporations from turning their rubles into foreign currency—even as it’s started to introduce them. It’s already ordered the big exporters to sell some of their dollars for rubles, and then keep their dollar reserves at that level from now on.

http://www.washingtonpost.com/blogs/wonkblog/wp/2014/12/26/putin-is-trying-to-save-russias-economy-with-one-weird-trick/