As much as $75 billion of Lehman Brothers Holdings Inc. value was destroyed by the unplanned and chaotic form of the firm's bankruptcy filing in September, according to an internal analysis by the company's restructuring advisers.

A less-hurried Chapter 11 bankruptcy filing likely would have preserved tens of billions of dollars of value, according to a three-month study by the advisory firm, Alvarez & Marsal. An orderly filing would have enabled Lehman to sell some assets outside of federal bankruptcy-court protection, and would have given it time to try to unwind its derivatives portfolio in a way that might have ...