LONDON (Reuters) - A top shareholder in Glencore (GLEN.L), Abu Dhabi's Aabar Investments, has written off more $392 million of its $1 billion investment in the commodities trader, less than two years after taking part in its record listing.

Aabar, a unit of Abu Dhabi's state-owned International Petroleum Investment Co INPTV.UL, became the largest new shareholder in Glencore when the mining-to-trading giant went public in May 2011, investing $1 billion.

According to financial statements filed by IPIC on Thursday, Aabar, which owns 1.4 percent of Glencore, has recognized an impairment loss of $392 million. It gave no further details.


Glencore's shares are trading almost 40 percent below an IPO price of 530 pence, underperforming by more than 10 percent a mining sector that has been hit by worries over cooling demand - despite hopes its marketing arm would help weather stormier times for the commodities markets.

The write-down comes as Glencore, the world's largest diversified commodities trader, moves into the final stages of its long-awaited takeover of miner Xstrata XTA.L, in which it is already the largest shareholder.

Qatar, which has become the second-largest shareholder in Xstrata, said on Thursday it would vote in favor of the deal.

IPIC said in the same interim financial statement that it had booked a fair value loss of $660 million on its shares in Italian bank UniCredit (CRDI.MI), though a gain of $51 million on its stake in automaker Daimler (DAIGn.DE).

IPIC said its profit for the six months to the end of June totaled $818 million, down from $1.16 billion a year ago. (Reporting by Clara Ferreira-Marques; Editing by Jon Hemming)