These "structured transactions" are so-named because they are based on multiple, carefully orchestrated terms. The transactions may include arrangements such as equipment leases, which may be used to keep billions in obligations out of plain sight.

"If you really believe that it's a good idea to structure things around the accounting or disclosure guidance, you shouldn't be embarrassed to tell readers of your reports that that's what you've done," said Scott Taub, deputy chief accountant in the SEC's Office of the Chief Accountant, at a speech Monday before the American Institute of Certified Public Accountants.

Structuring transactions to make the most of accounting standards doesn't necessarily violate securities regulations. Still, regulators are scrutinizing financial arrangements and punishing companies when it decides their actions cross the line.

"These types of arrangements work sometimes, and other than requiring proper disclosure, there isn't much I can do to dissuade them," Taub said. "But I don't have much sympathy for a company that attempts to design a transaction around the literature and fails."

Only last week, American International Group Inc. agreed to pay $126 million to resolve charges the insurance giant had marketed products that improperly helped companies take deteriorating loans and investments off their books.

The calls for better disclosure of complex transactions comes amid a broader push for financial statements that are easier to read and more useful to investors.

"We need to broaden investor understanding of what information is important in terms of making investment decisions," said SEC Chief Accountant Don Nicolaisen in a separate speech on Monday. "So I would ask you to reflect on the type of information you require before you, your company, or your firm makes a major investment decision," he said. "Do you make similar information readily available in an unvarnished manner to the public?"