According to various news sources, the Securities and Exchange Commission is seeking detailed information from nearly two dozen large Wall Street financial and insurance companies about transactions known as repurchase agreements. More specifically, the SEC is investigating how commonly Wall Street firms have used the same accounting techniques that Lehman Brothers used to hide a firm’s losses.

In a 2,200 page report, Lehman’s bankruptcy examiner said the firm used repurchase agreements to hide some of its mounting debt before it collapsed in 2008. The firm hid the full force of its leverage by giving sale treatment to assets it had an obligation to repurchase, shuttling off the balance sheet as much as $50 billion in failing assets.

More specifically, the SEC’s Division of Corporation Finance send a letter to a few dozen banks and insurance companies asking for specific information on how they account for repurchase agreements, securities lending transactions, and other transactions that involve the transfer of assets with an obligation to repurchase them.

Further, the letter asks for a long list of detailed information about such transactions if they received sale treatment, how much in each quarter for each of the past three years, how a repurchase qualified for sale treatment vs. a collateralized financing, how it was analyzed, what business reasons were behind it, how it affected key ratios that indicate financial performance, and plenty more.

The SEC didn’t name specifically who received the letter, but it posted a copy of the letter to its website. The letter doesn’t mention Lehman Brothers, but those are precisely the transactions Lehman stretched to the point of abuse in its desperate lunge for survival. SEC Chairman Mary Schapiro has said the agency is “looking broadly” at the financial sector to determine whether other companies may be using a similar technique.

The SEC asks for a written response in 10 days. “Upon our review of your responses to these questions, we may have additional comments that we will provide to you with any other comments we may have on your Form 10-K,” the letter promises, signed only “Senior Assistant Chief Accountant.”