A COURT-APPOINTED investigator is this week expected to shine fresh light on the role of JP Morgan and other financial institutions in the events running up to the collapse of Lehman Brothers, the American investment house.

Anton Valukas, a whitecollar crime specialist who played a leading role in the Conrad Black fraud investigation, was recruited by a New York bankruptcy court. His long-awaited report, which is understood to run to more than 1,000 pages, should be published this week.

It will focus on whether JP Morgan, Lehman’s main short-term lender, dealt a fatal blow to the bank by increasing collateral demands on loans in the days immediately before its demise.

Valukas’s findings will be pored over by all those who lost money in Lehman’s collapse, and by the Lehman estate, which holds the bank’s residual assets and is charged with recovering money for creditors. According to one source, the estate, which represents the interests of all the bank’s creditors, is planning to launch a $17 billion (£11 billion) claim against JP Morgan.

That would mirror a complaint lodged with the court by the bank’s creditor committee in the immediate aftermath of the bankruptcy filing. This claim, made in October 2008, cites the $17 billion figure as the amount of Lehman cash and securities that JP Morgan “froze” in its final days, precipitating the largest collapse in corporate history.

JP Morgan has emerged as one of the strongest survivors of the credit crunch. Last week it paid its boss, Jamie Dimon, a $17m bonus. If it is singled out in the report, it could trigger multi-billion-dollar claims from Lehman’s creditors and bondholders. One bondholder said: “This is just the first move. We will be going after JP Morgan for a long time.”

The investigation will also look at whether the Federal Reserve got preferential treatment as a creditor. Before Lehman filed for bankruptcy, the Fed lent it $46 billion in cash and securities. This was repaid promptly while other debts running into tens of billions of dollars have been left to be resolved in court.

-Source