SINGAPORE - Commodities firm Noble Group continued to see its share price tumble on Monday following two reports alleging accounting malpractices by anonymous firm Iceberg Research.

Noble shares stood at 93 cents at 1.10pm on Monday, down 4.5 cents from its close at 97.5 cents on Friday, with heavy trading of 50.9 million shares.

They are down by about 22.8 per cent since they closed at $1.205 on Feb 13, a day before the first report by Iceberg was published.

Bloomberg News said two analysts cut their rating on the stock to hold, citing weaker than expected earnings and concern over a possible third critical report by the anonymous group, Iceberg.

Noble is now rated a hold by five brokers and a buy by 11 from three holds and 12 buys before the Iceberg report, said Bloomberg. The consensus 12-month target price has fallen to $1.37 a share, the lowest since May last year, according to data compiled by Bloomberg.

The mainboard-listed company, which is based in Hong Kong, reported an unexpected US$240 million loss for its fourth quarter last week, largely due to a US$438 million writeoff.

The impairments included a US$200 million loss on Yancoal Australia Ltd., a company in which Noble owns 13 pe rcent, and which was at the centre of Iceberg's allegations in its first report that Noble overstates the value of associate companies on its books, a charge that the trading house denies.

Its chief executive officer Yusuf Alireza said last week that he believes that a "disgruntled" employee fired a year and a half ago is behind the Iceberg reports and it has passed on this information to the Monetary Authority of Singapore.

He also rejected allegations in Iceberg's second report published Feb. 25, which criticised the way Noble handles its cash flow and fair value.