* Abu Dhabi fund files lawsuit; Noble says to defend itself
* Company has sold assets, taken writedowns in past 3 years
* Noble is seeking a crucial debt restructuring deal
* Noble's shares have collapsed from Feb 2015
* Richard Elman steps down from Noble's board (Adds fresh Noble Group comment in 10th and 11th paragraphs)
SINGAPORE, March 21 (Reuters) - Goldilocks Investment Co, a leading shareholder of Noble Group Ltd, has filed a lawsuit with the Singapore High Court against the commodities trader and some of its former and current senior executives, alleging they inflated Noble's assets.
"We have filed it today," Daniel Chia, a Morgan Lewis Stamford lawyer who is representing Goldilocks, an Abu Dhabi Financial Group equity fund, said late on Tuesday.
The move comes days after Singapore-listed Noble said it would not make the redemption payment for its $379 million bonds which matured on Tuesday. Noble is seeking a $3.4 billion debt restructuring that is crucial for its survival.
Noble's restructuring deal has been opposed by some bondholders and shareholders such as Goldilocks, which has an 8.1 percent stake in the trading company. The fund was not available for comment.
In a filing to the Singapore bourse on Wednesday, Noble said its founder and chairman emeritus Richard Elman had resigned on Tuesday as a non-executive director. It gave no reason for the resignation of the 77-year-old executive.
Elman founded the company in 1986 and then rode a commodities bull run to build it into one of the world's biggest traders.
Hong Kong-headquartered Noble has been negotiating a debt-for-equity swap for months after selling billions of dollars of assets, taking hefty writedowns and cutting hundreds of jobs over the past three years.
The lawsuit filed on Tuesday alleges that some of the defendants "sanctioned aggressive revenue recognition and creative accounting policies in order to inflate the valuations of Noble's 'associate companies' and long-term commodity contracts."
"The objective of these overvaluations was to inflate Noble's revenue and balance sheet," according to a copy of the 72-page filing seen by Reuters.
On Wednesday, Noble confirmed it had been served a "writ of summons" by Goldilocks.
"The company is in consultation with its legal advisors in this regard and intends to vigorously resist any and all allegations or claims made against it," Noble said in a statement to the Singapore stock exchange.
Once Asia's largest commodity trader, Noble was plunged into crisis in February 2015 when Iceberg Research questioned its books. Noble has stood by its accounting.
Last week, Noble said it had finalized the restructuring agreement with a group of senior creditors holding 46 percent of its debt, and was in talks with others.
Under the deal, Noble is seeking to halve its senior debt and hand over 70 percent of the restructured business to creditors.
Noble's market value has fallen to just $114 million, from $6 billion in February 2015, as the company reported record losses and shrunk its business.
Late on Tuesday, S&P Global Ratings cut Noble's credit rating to "D," implying a default, as it said Noble had missed the principal and coupon payment for its 2018 notes due the same day. ($1 = 1.3177 Singapore dollars) (Reporting by Anshuman Daga; Editing by Sumeet Chatterjee and Dale Hudson)