Citi: US stocks have priced in expectations of a Democratic sweep; Senate seats will determine the next move

Why does the Senate result matter more than whether control changes hands?

Citi sees Democratic control of both the House and Senate as the most likely outcome, which is largely reflected in current US equity sentiment; a Democratic takeover of the House is also widely expected by the market.
But polling margins in several key Senate races are within the margin of error. Citi believes an unexpected Republican hold on the Senate could push US stocks higher through year-end; a larger-than-expected Democratic majority could put additional pressure on equity valuations.
As of the report, the average generic congressional ballot showed Democrats ahead by 8.1 percentage points, while Trump's net approval rating was negative 21.7%. Citi believes this combination resembles the backdrop to the Republicans' 2006 midterm defeat.

Under the scenario in which the polling and prediction-market leaders in all the key states listed in the report win, Democrats would hold 53 Senate seats. But margins in several swing states are narrow, and even a small overall polling error could swing a group of seats to the other side.
Senators serve 6-year terms, and most Democratic seats up for election in 2028 are in safe states. Citi believes that winning 53 seats or more this time would increase the probability that Democrats control both chambers of Congress in 2028, leading markets to price in the risk of higher corporate taxes earlier.
The size of the House majority also matters: a larger majority gives some lawmakers room to depart from the party line on key issues, improving their chances of retaining their seats in 2028. Citi is particularly focused on the combination of Democrats winning more than 235 House seats and more than 53 Senate seats.

Citi's earlier preference for healthcare over financials and banks has largely played out. The bank believes a Democratic takeover of the House alone would open the door to increased healthcare spending, and a divided Congress could reverse some previous cuts through budget negotiations.
If Republicans hold the Senate, Citi expects financial stocks could rise: control of Senate committees can influence regulatory expectations, and the Senate also has the power to approve the Federal Reserve nominee for Powell's seat.

Citi believes that if Democrats win more gubernatorial and local elections, state legislation and local zoning and permitting processes could face more obstacles, limiting the pace at which new computing capacity comes online. Election results in individual states such as Texas could also affect the relative performance of different AI-related assets.
The bank is less concerned about long-term fundamentals: it believes planned capacity is generally more likely to come online later than to be canceled on a large scale; a slower construction pace could also ease market concerns about funding pressure.

Citi expects the midterms to have a limited immediate impact on fundamentals, with the near-term effects more likely to appear as swings in market sentiment about policy expectations.
As 2027 begins, the budget, debt ceiling and deficit financing could return to the spotlight. As Democrats seek higher healthcare spending and Republicans push for higher defense spending, concerns about larger deficits will coexist with the positive effects of fiscal stimulus.