Dick Fuld, the ousted chairman and chief executive of Lehman Brothers, and his deputies cost creditors as much as $75 billion (£51.5 billion) by rushing the stricken investment bank into a bankruptcy filing, an analysis by liquidators has found.

Bryan Marsal, co-chief executive of Alvarez & Marsal (A&M), which is restructuring Lehman, described the bank's unexpected collapse on September 15 as “unconscionable waste of value”. Mr Marsal's report estimates that between $50 billion and $75 billion of assets that could have been used to repay unsecured creditors were wasted because Lehman did not have a clear plan to wind down the bank.

A&M was hired by Lehman's board at 10.30pm on September 14, hours before Lehman made the biggest bankruptcy filing in American history. The US Government had refused to bail out Lehman as it had Bear Stearns in March and Mr Fuld's pleas to rivals, including Bank of America, to buy the business had fallen on deaf ears.

Mr Fuld had spent months assuring investors that the bank was financially sound, while turning away offers that he considered too low. In his first internal report, Mr Marsal made a series of damning accusations about the actions of top Lehman executives in the lead-up to the bank's collapse.

Mr Marsal said: “This [bankruptcy]filing, which was pretty much dictated to the board of directors at Lehman that weekend, occurred with no planning. Had rules of crisis management been followed, much of the value that was lost by the unsecured creditors would have been prevented.

“While I have no position on whether or not the Federal Government should have provided further assistance, once the decision was made not to provide it, an orderly wind-down plan should have been pursued.”

Lehman's unsecured creditors are owed an estimated $200 billion but are expected to recover only $20 billion, ten cents on the dollar, once the restructuring is complete. A&M found that most of the loss of value had occurred because the bankruptcy filing caused the bank to default on trading contracts with counterparties, cancelling about 900,000 derivatives contracts. These included contracts in which Lehman was owed money. In an orderly unwinding, at least $50 billion could have been saved, A&M found.

Further value was destroyed when the unplanned bankruptcy forced down prices for Lehman's assets in a market already artificially depressed by the shock collapse of the bank. This meant that the trading and investment banking businesses were sold for less than $500 million although they had made about $4 billion annual profits before the bankruptcy.

About 150 A&M liquidation experts are working at Lehman's New York, London and Hong Kong offices to ascertain what assets can be salvaged for creditors. Mr Marsal will take over as Lehman's chief executive when Mr Fuld stands down at the year-end.

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