SINGAPORE, June 22 (Reuters) - Goldilocks Investment Co, an equity fund which is part of Abu Dhabi Financial Group, said on Thursday it had increased its stake in embattled commodity trader Noble Group to 5 percent.

The increase came as the crisis-hit trader extended a key debt deadline earlier this week and continued talks with potential investors to boost liquidity.

The Singapore-listed firm has been buffeted by a collapsing share price, credit downgrades, management upheavals and a series of writedowns and asset sales.

Its shares tumbled 12.5 percent on Thursday to close at S$0.455, down from a 2011 peak of about S$17.

Goldilocks, which previously owned 1.18 percent of Noble shares, said it purchased an additional 50.546 million shares on Tuesday to take its take to 5.0 percent.

The fund did not elaborate in its filing to the Singapore stock exchange why it increased its stake in Noble.

(Reporting by Miyoung Kim; editing by David Clarke) ((miyoung.kim@thomsonreuters.com; 65 6870 3026; Reuters Messaging: miyoung.kim.thomsonreuters.com@reuters.net))