Abu Dhabi is assessing its $7.5 billion investment in Citigroup as the bank's problems deepen and consequences of a possible nationalization become clearer, according to sources close to the Abu Dhabi Investment Authority (ADIA).

ADIA invested $7.5 billon last year in Citi through convertible bonds that pay 11 percent in interest, but it must start converting the bonds into 235.6 million shares in Citigroup from March next year.

Nothing has changed from ADIA's perspective at this point. ADIA's convertible bonds are due for conversion in a phased manner between March 2010 and September 2011, and that stands, an Abu Dhabi government official told Reuters.

But it is carefully assessing its options due to the latest events -- although no decision is taken yet, he said declining to be named due to confidentiality issues.

A spokesman for ADIA, thought to be the world's largest sovereign fund, declined to comment.

(Reporting by Stanley Carvalho; Editing by Thomas Atkins/Will Waterman)

United arab emirates Citigroup Investment