SINGAPORE (July 30): Commodities trader Noble Group slumps 9.3% to 53.5 cents a share, its lowest level since December 2008 despite no immediate cues for trading.

The company has been buying back its stock for more than a month, but the impact on its share price appears to be minimal.

Sales data show seven trades during Thursday's session of more than 500,000 shares each, at prices between 57 cents and 54 cents.

Noble Group stock has been battered over the past few months after three analyst outfits claimed accounting irregularities in its financial statements.

Noble denies any wrongdoing.

The stock has nearly halved in value in the year to date.