The Securities and Exchange Commission is investigating how commonly Wall Street firms have used the same accounting maneuvers that Lehman Brothers used to hide mounting debt.

The SEC’s Division of Corporation Finance sent 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. 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, according to the firm’s court-appointed bankruptcy examiner.

In a 2,200-page report, Lehman’s bankruptcy examiner said 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.

The SEC didn’t name specifically who received the letter, but it posted a copy of the letter to its Website—a kind of shot across the bow for any company engaging in repurchase agreements and giving them sale treatment to get them off the balance sheet. 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 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.”

Bruce Pounder, president of accounting education firm Leveraged Logic, said it’s not entirely clear that Lehman’s accounting is out of compliance with Generally Accepted Accounting Principles. “It's a wise move on the SEC's part to gauge how widespread such accounting practices are before taking any sort of action,” he said. “But I will say that users of financial statements are none too pleased that this sort of accounting apparently can and does happen.”

Compliance Week will have more on the letter in an upcoming edition.