US Securities and Excchange Commission Chairwoman Mary Schapiro said that the agency is weighing new rules to prevent financial firms from masking debt through accounting maneuvers.

Schapiro made her comments early on at the Lehman Brothers hearing. A bankruptcy examiner revealed last month that Lehman used an accounting gimmick, called “Repo 105s,” to mask some $50 billion in debt.

“We are considering under SEC rules we need new rules to prevent the sort of masking of debt and liquidity at quarter’s end as we saw Lehman do,” Schapiro told the committee.