MUMBAI - India's central bank bought a net $3.99 billion rupees from the spot foreign exchange market in December compared to a net purchase of $10.26 billion in December, its monthly bulletin released on Monday showed.

The Reserve Bank of India bought $10.01 billion while it sold $6.02 billion in December, data showed. The rupee had moved in a range of 73 to 73.96 per dollar in December.

The net outstanding forward purchase stood at $39.79 billion as of end-December, compared with a net purchase of $28.34 billion at the end of November.

The RBI also bought dollars in the currency futures market, with the outstanding net currency futures position rising to $1.96 billion at the end of December, compared to $780 million at the end of the previous month.

The RBI intervenes in the foreign exchange market to curb excessive volatility in the rupee. The currency was at 73.47 to the dollar on Friday.

(Reporting by Swati Bhat; Editing by Subhranshu Sahu) ((swati.bhat@thomsonreuters.com; twitter.com/swatibhat22; +91-22-68414381; Reuters Messaging: swati.bhat.thomsonreuters.com@reuters.net))