The results of the US midterm elections on November 3 could affect Wall Street, AI stocks, US Treasury yields and the country's financial outlook. Investors are closely watching whether Democrats or Republicans will control Congress after the elections. The election results could increase concerns about heavy spending on artificial intelligence (AI), future tax policies and negotiations over the US debt ceiling.A Democratic victory could also lead to more investigations into major American companies, including AI firms and Wall Street businesses.

Although US midterm elections do not usually cause major market movements, this year's results could create fresh uncertainty for investors, according to Reuters.US stock market gains 27% under TrumpSince Donald Trump returned to the White House in 2025, Republicans have controlled both the White House and Congress. During this period, the S&P 500 has gained around 27%. The stock market's rise has been supported by heavy spending on AI technology and strong company earnings. However, US Treasury yields have also increased considerably during this period.US midterm elections 2026 LIVE: Democrats, Republicans see close contest; Justice dept intervenes in mail-in ballot caseCurrent forecasts suggest that Democrats are likely to win control of the House of Representatives.

However, the fight for control of the Senate remains uncertain. Democratic win could increase AI rules and Wall Street scrutinyIf Democrats win control of both the House and Senate, investors expect greater government scrutiny of AI companies.

Democratic lawmakers could investigate major companies and their business practices.AI companies could face stricter safety rules and more investigationsThese rules could include:Safety standards for advanced AI systems. Independent checks to test whether AI models are safe. Mandatory reporting of serious AI-related incidents. Greater responsibility for companies building and operating data centres. Such measures could increase compliance costs and create new challenges for AI companies.

Raymond James Washington policy analyst Ed Mills said congressional investigations could increase pressure for these rules and make data centre developers more accountable, according to Reuters. Growing opposition to data centres could create problems for AI stocksPublic opposition to new data centre projects could create difficulties for companies planning to expand their AI operations. According to a Reuters/Ipsos opinion poll, only one in three Americans approve of the fast pace of data centre construction.

More congressional investigations could increase pressure on these projects and affect investor confidence in AI expansion. Oil prices fall over 4% as US-Iran peace talks raise hopes of easing Middle East supply disruptionsA Democratic victory in either or both chambers would give the party greater power to investigate American industries and government regulators. Wall Street companies, banks and crypto businesses could face greater scrutiny. Democrats are already preparing to investigate links between Donald Trump, his family and the crypto and prediction market industries.

Divided Congress could affect US debt and Treasury yieldsIf Democrats win the House but Republicans retain control of the Senate, the US will have a divided Congress. This could make it harder for lawmakers and the White House to agree on important economic and spending decisions.A divided Congress could make negotiations over government borrowing more difficult.

The US debt ceiling is expected to become an important issue again in 2027. If Democrats and Republicans fail to reach an agreement, the country could face another period of political uncertainty over government borrowing, according to Reuters. Investors are closely watching how election results could affect US government spending and borrowing. Higher government borrowing and rising interest costs could add to concerns about US Treasury debt. This could influence demand for US government bonds and the direction of Treasury yields.

The US dollar could weaken if political disagreements hurt economic growthPolitical disputes between the White House and Congress could create uncertainty about future economic policies. Investors may worry that repeated disagreements over government spending and borrowing could slow economic growth. If markets believe that political uncertainty will hurt the US economy, the dollar could come under pressure. The currency could also face pressure if investors become less confident about the country's financial outlook.A Democratic takeover of the House could create some uncertainty for the stock market.

More investigations and political disagreements could affect investor confidence. Ed Clissold, chief US strategist at Ned Davis Research, said a Democratic House takeover could slightly slow the stock market's year-end rally, according to Reuters. Republican win could support AI stocks but raise US debt concernsIf Republicans retain control of both the House and Senate, the Trump administration could continue its existing economic and business policies.

Investors may expect fewer new federal regulations and less congressional scrutiny of AI companies. The administration could also make it easier for companies to get federal approvals for new projects.JPMorgan strategists said a Republican victory could provide a supportive policy environment for AI and infrastructure investments.

They pointed to policy continuity, possible higher government spending, deregulation and faster federal approvals as factors that could support the sector, according to Reuters.A Republican sweep could allow the Trump administration to push ahead with more tax reforms. The government could also increase defence spending. However, additional tax changes and higher defence spending could also increase the government's budget deficit. This could create fresh concerns about the country's financial position. These policies could involve more tax reforms and higher government spending.

If government spending increases without enough additional revenue, the US could need to borrow more money. Joaquín Kritz Lara, chief economist and strategist at Numera Analytics, said a Republican sweep would confirm the continuation of Trump's and Treasury Secretary Scott Bessent's fiscal policy approach. He warned that more tax changes or a major increase in defence spending could worsen the US government's financial position, according to Reuters. However, this support may not last if investors become worried about higher government borrowing and growing deficits.

Karl Schamotta, chief market strategist at Toronto-based payments company Corpay, said a clear Republican victory could initially support the dollar through higher Treasury yields, according to Reuters. However, he warned that continued deficit-funded spending, pressure on institutions and foreign policy risks could make investors increase their currency hedging over time.