Traders on the floor of the New York Stock Exchange.

A U.S. debt default would create significant confusion and uncertainty in financial markets and could prove as catastrophic as the failure of Lehman Brothers in 2008, the Organization for Economic Cooperation and Development (OECD) said in a new report.

Lawmakers in the U.S. side-stepped a debt default at the 11th eleventh hour in October and brought an end to prolonged negotiations over raising the debt ceiling. But talks are set to resume in the new year with the debt ceiling extended until February 7 and funding approved until January 15.