The main US indicators closed slightly more than 0.5% on Tuesday as voters went to the polls.
Markets are stabilizing for a retention period, better or worse. None of the parties is likely to hold several votes to adopt clear legislation. Although this may mean that the Republicans and President Donald Trump have failed to cut taxes further, it also means that current tax cuts can not be reversed.
"The mid-term elections this week could lead to a shift in power balancing in Washington, but are unlikely to bring any short-term policy changes," Richard Turnill, head of BlackRock's global investment strategy, told clients before the results.
If Congress is divided, as it now seems likely to be, America's fiscal, regulatory and monetary policy may remain the same. Investors usually do not have the mind, they say cynically it means that Washington can not be shuffled.
"We see little continued market impact if in the medium term they reach a divided Congress," Turnill writes.
"We expect financial deadlines to become more disruptive," said Goldman Sachs analysts in a report this week.
Markets, especially the bond market, could have a more dramatic response if the Republicans keep control of Congress. In this scenario, Goldman Sachs expects a tax cut of around 0.3% of GDP to come into force in mid-2019.
The bond market may be rebellious if Washington adds to the nation's existing budget deficit. Most tax cuts will lead to more borrowing and possibly higher bond yields.
Daniel Shane contributed to this report.