According to Bloomberg, the battle for control of the U.S. Congress has cost more than $10 billion, far more than the presidential election. Control of Congress is crucial to economic policy, involving legislation such as tax laws, drug prices, and the crypto industry.

Republicans are expected to gain a majority in the Senate, while Democrats have a chance to control the House of Representatives, which could result in a split between the two chambers. Key races include Montana, Ohio and other states, and the results may be known a few days after the November 5 election.

The Democrats' hopes in the Senate rest on candidates like Tester in Montana, while Republicans could win as many as 55 seats in swing districts. In the House of Representatives, Democrats are challenging for a majority in New York, California and other states.