NEW YORK, Jan 10 (Reuters) - Citigroup has announced a combined $2.1 billion in charges and reserve builds for the fourth quarter, according to a filing on Wednesday.

The bank said it will book a $1.3 billion reserve build for currency exposures outside the U.S., especially in Argentina and Russia.

The bank will also book $780 million in restructuring charges that include severance and other related charges, according to the filing. (Reporting by Tatiana Bautzer Editing by Chris Reese)