Nearly five months after revelations of questionable repurchase accounting at Lehman Brothers, the Financial Accounting Standards Board is taking up a new project to see if it can plug holes in accounting rules that allowed it to happen.

FASB Chairman Robert Herz told the board in a recent regular meeting he is opening a “very targeted scope project” to look at the accounting rules regarding repurchase agreements and any other contractual arrangements where two parties are both entitled to and obligated to an exchange of some kind. Herz said the project is in response to bankruptcy proceedings for Lehman Brothers.

The examiner in the Lehman Brothers bankruptcy proceedings concluded Lehman hid debt by accounting for repurchase agreements as true asset sales, shuffling as much as $50 billion in assets off the balance sheet at key financial reporting intervals. The Securities and Exchange Commission has queried a few dozen other financial institutions to ferret out any similar practices, although a recent study from Audit Analytics suggests the SEC has been at least taking note of the accounting for repurchase agreements for some time.

Herz told the House Financial Services Committee in April that he couldn’t pass judgment on whether the accounting was appropriate, and he didn’t offer any further view on Lehman’s application of the accounting rules when he spoke to the board last week. However, he’s apparently heard and read enough in the nearly five months since the Lehman report emerged to decide the rules need a once over.

“Once we’re made aware that people are trying to structure around specific provisions in the accounting literature, it makes you think about whether those provisions need to be looked at,” he told the board. “We’ve asked the staff to take a look at that and come back with some recommendations in the pretty near term,” he said.

The accounting for repurchase agreements has not changed since 1997, although FASB recently gave companies some significant new guidance on when and how to consolidate entities that otherwise have remained off corporate balance sheets. The board adopted Accounting Standards Updates No. 2009-16 and 2009-17 to eliminate certain off-balance-sheet treatments that enabled significant risks to remain hidden from investors.