SINGAPORE - Embattled commodities trader Noble Group on Wednesday issued an open letter in response to its fierce critic, former Temasek senior managing director Michael Dee, saying that the group has responded to all questions and its stakeholders were satisfied with the replies.

Chief executive Yusuf Alireza said that the Group does not have off-balance sheet repos nor does it execute optional inventory sales, and that the company would comply with any change in accounting rules if need be.

The four-page letter was in response to an open memo by investment banker Mr Dee to Noble's staff on May 29, in which he rehashed his criticism of the group's lack of transparency and pressed its management to answer questions that have been raised about the company. Mr Dee had also appealed to Noble's founder and chairman Richard Elman to resign, saying that he had lost credibility with investors given the fall in its share price, compared to gains in the Straits Times Index, in the past five years.

Noble stock had come under new selling pressure after the letter.

"Noble Group does not overvalue Yancoal on our balance sheet as Mr Dee has repeatedly alleged," Mr Alireza's letter stated. "Noble values its associate stake using a cash flow model rather than a market price because an 8 per cent free float, A$15,000 average daily trading volume, and 5x share price rise in two months, are not the characteristics of a liquid and transparent stock price. Noble's valuation approach is reasonable and consistent with practice in the mining industry and accounting policies."

The letter also added: "Up to now I have chosen to ignore your ill-informed opinions. However, your recent call for the resignation of our founder and chairman is a step too far."

Noble's shares have been under pressure since February, following questions raised by critics about its accounting practices and amid a weak outlook for commodities. It announced on Tuesday that it had made market acquisition the day before of close to 12.98 million shares for about S$9.22 million, averaging 70.87 Singapore cents apiece.

This was its third buyback in a week, with such share repurchases now totalling S$42.9 million in value.