Jamie Dimon warns of potential catastrophe as US approaches debt default.

JPMorgan CEO Jamie Dimon warns that a US debt default is "potentially catastrophic" and urges politicians to strike a deal. The clock is ticking for lawmakers to lift the debt limit, with Treasury Secretary Janet Yellen warning that the country could run out of money as early as June 1 if the ceiling is not raised. JPMorgan is preparing for the risk of a default, convening weekly "war room" meetings. Republicans have promised to raise the borrowing limit only in exchange for deep spending cuts, while Democrats have refused to negotiate and insisted on a "clean" debt ceiling bill that does not include any cuts.