Stocks took a steep post-Election Day plunge, as investors worried that a returning President Obama and Republicans will fail to reach a deal to head off a slew of tax increases and spending cuts scheduled to kick in at the start of next year.

The Dow Jones industrial average dropped 313 points, or 2.4 percent, to 12,932.73, its worst one-day showing of 2012. Analysts said investors were imagining a worst-case scenario in which Obama and lawmakers fail to reach a compromise in time.