US midterms: can the Democrats retake both houses, and what would that mean for investors?
Macroeconomic forces have typically mattered more for markets than the midterms. Yet the fiscal fights, sector scrutiny and trade tensions that follow Donald Trump’s midterm elections in November 2026 could shape market outcomes long after the votes have been counted – especially if the Democrats make significant gains.
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Midterm elections are usually seen as a referendum on the occupant of the White House. Rarely has the incumbent emerged unscathed, with the president's party losing seats in the House of Representatives in all but two midterms since World War II.
President Trump's first midterms in 2018 were no exception, with Republicans losing 41 seats. History suggests his current approval rating could produce a similar outcome in November, far exceeding the two-seat loss the party can afford.
The House looks settled. The Senate does not.
The Senate is a different contest. Only around one-third of seats are up for election and the states involved matter as much as the national political mood. Democrats need a net gain of four seats while also defending their existing ground. Competitive races in states such as North Carolina and Maine offer opportunities, but vulnerabilities elsewhere mean several contests must break their way simultaneously. As things stand, the Republicans remain marginal favourites to retain control of the chamber.
Either way, Republicans are all but certain to lose their trifecta (combined control of the White House, House of Representatives and Senate) in November. A split Congress remains the most likely outcome, but the Senate is finely balanced enough that a Democratic sweep would hardly come as a surprise.
For investors, the distinction matters because it will influence the intensity of fiscal fights and sector scrutiny over the next two years.
The House is likely to flip, but the Senate is all to play for
Source: The American Presidency Project, Macrobond, Schroders Economics Group. 21 August 2026.
One blue chamber or two?
If Democrats take the House, they will be able to frustrate the administration's agenda. The House could block partisan legislation, launch investigations and shape the political debate. However, the Republican Senate would continue to provide the White House with an important defensive barrier. The result would be greater oversight, more political noise and a higher risk of fiscal confrontation, but limited scope to reverse the administration's broader policy agenda.
A Democratic sweep would tighten those constraints. Control of both chambers would allow Democrats to intensify investigations, increase scrutiny of politically sensitive sectors and exert greater influence over appointments and nominations. Yet even then, President Trump would retain the veto and substantial executive authority. A Democratic sweep would therefore constrain the administration rather than fundamentally alter the direction of policy.
For investors, the difference is likely to be one of degree rather than direction. Either scenario of a split Congress or a Democratic sweep would increase political friction in Washington. The latter would simply amplify those pressures. As a result, the most important market consequences are likely to stem not from the election result itself, but from the policy confrontations that follow.
Gridlock could come with a larger fiscal bill
Whichever outcome materialises, the debt ceiling is likely to become an early flashpoint for the new Congress. That challenge has become more acute with US federal debt now above $40 trillion. Based on the current trajectory and the extraordinary measures available to the Treasury, the X-date is likely to be reached around the middle of 2027. A Democratic House would have considerable leverage over any agreement, while control of the Senate would strengthen that position further.
But investors should be wary of assuming that gridlock automatically means fiscal restraint. Initially, markets may conclude that the loss of the Republican trifecta would make another large tax or spending package more difficult, potentially bringing some near-term relief to Treasuries. That reaction would be understandable. Historically, divided governments have often been associated with fewer opportunities for deficit-financed stimulus. But this time could prove different.
The likely fault lines are already visible. Republicans want higher defence spending. Democrats want to reverse cuts to Medicaid in the administration's One Big Beautiful Bill. Given the increasingly confrontational nature of fiscal negotiations in recent years, neither side may be willing to concede much ground. A last-minute compromise could therefore accommodate both demands rather than force either side to retreat. By our estimates, this could widen the deficit by around 1% of GDP.
This creates a two-stage risk for Treasuries. Yields could initially fall after the election as investors price less near-term fiscal expansion. But they could reverse higher as the debt-ceiling negotiation approaches and attention shifts from legislative restraint to the cost of the eventual compromise. The key issue is not the additional borrowing itself, but what it signals about fiscal discipline. If political compromise increasingly means larger deficits rather than fiscal consolidation, investors may demand a higher term premium to hold long-dated Treasuries, resulting in a structurally steeper yield curve.
Partisan divide could set up debt ceiling standoff in 2027
Source: Macrobond, Schroders Economics Group. 21 August 2026.
Sector dispersion may be the real equity story
Markets have generally welcomed divided government, judging that legislative gridlock allows companies to operate with fewer policy surprises. Yet the composition of Congress has historically had little bearing on the overall performance of US equities. Earnings, growth, inflation and rates have mattered far more. The more credible implication of the midterms is therefore greater dispersion between sectors rather than a materially different outcome at the aggregate level.
By controlling the House, the Democrats will be able to launch investigations and hold hearings. But extending their reach to the Senate would broaden that oversight by putting committees in both chambers under the party’s control. The resulting scrutiny could be particularly important for politically sensitive sectors such as energy, healthcare and technology. Consistent with this, our analysis suggests these sectors have often traded alongside changes in betting odds for Senate control.
Midterms matter for equities on sectoral not aggregate basis
Source: Macrobond, Schroders Economics Group. 21 August 2026.
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