US Midterm Election Results Out: Democrats Control Both Houses of Congress, What Should US Stock Investors Watch Next?

TradingKey - As the results of the 2026 U.S. midterm elections continue to roll in, Democrats have won control of the Senate and are close to securing a majority in the House of Representatives. While the shift in congressional power could strengthen checks on the Trump administration, election-related uncertainty is waning for financial markets, and investor focus is shifting back to corporate earnings, interest rates, energy prices, and returns on AI investments.

Historical experience shows that betting on specific sectors based on election outcomes does not always play out as expected. While policy direction is important, a company's ability to win customers, manage financing costs, and turn investments into profit typically plays a bigger role in driving stock price performance. Therefore, following the election, rather than chasing short-term political themes, investors should pay closer attention to which economic and business variables could genuinely impact earnings over the coming quarters.

How Shifts in Congressional Power Affect Fiscal and Regulatory Policy

If the Democratic Party ultimately controls both houses of Congress while the White House remains under Republican control, the United States will enter a state of divided government. Checks and balances between the two parties could reduce the likelihood of passing major tax, spending, and regulatory legislation; however, trade, tariffs, immigration, and certain industrial policies can still be advanced through executive orders or federal agencies.

Markets will next focus on congressional investigations, government budget negotiations, and debt financing arrangements. Particularly with the fiscal deficit remaining elevated, the scale of U.S. Treasury issuance could continue to affect long-term yields. Even if political gridlock reduces new spending, significantly narrowing the deficit through spending cuts or tax adjustments remains highly challenging.

This means that the conclusion of the midterm elections will not necessarily bring lower interest rates. If U.S. government financing needs remain elevated, the 10-year Treasury yield could stay high, thereby weighing on high-valuation tech stocks and raising the cost of capital for corporate investments in data centers and AI infrastructure.

Can Corporate Earnings Support US Stock Valuations

With the election behind us, corporate earnings will once again become the primary factor driving the direction of U.S. equities. During this earnings season, although some major tech companies maintained revenue growth, they were sold off due to expanding capital expenditures, pressure on free cash flows, or weak earnings guidance. This indicates that the market is no longer satisfied with simple AI growth stories, but instead demands that companies prove their investments can generate tangible returns.

Data center spending, depreciation costs, and margin changes at major cloud computing companies over the coming quarters will continue to impact Nvidia (NVDA), AMD (AMD), Broadcom (AVGO), Lumentum (LITE) and Coherent (COHR) in optical communications, as well as ASML (ASML) and Applied Materials (AMAT) in semiconductor equipment, alongside other companies across the AI value chain. If revenue from cloud services and AI products can consistently outpace the growth rate of infrastructure costs, the sector could still find growth support; conversely, if capital expenditures continue to rise while revenue and profit improvements remain limited, tech stock valuations may face further contraction.

Beyond the tech sector, the performance of banking, consumer, and industrial companies also needs to be evaluated in light of interest rates and economic growth. Whether high interest rates are beginning to squeeze credit demand, whether consumer spending can remain resilient, and whether companies continue to expand hiring and investment will all influence market assessments of earnings growth in 2027.

AI Data Center Approvals and Power Supply Worth Watching

The impact of the midterm elections on the AI industry is likely to be felt more at the state and local levels. Data center construction requires land, power, transmission infrastructure, and local government permits, and whether projects can move forward smoothly will increasingly depend on electricity pricing arrangements, community attitudes, and developers' willingness to bear infrastructure upgrade costs.

Morgan Stanley believes U.S. AI infrastructure investment will continue to expand, but the buildout process may enter a phase of "conditional progress." Local governments may require data center operators to shoulder more grid construction and energy costs, thereby altering project costs and timelines for coming online.

Investors therefore need to distinguish between companies that already possess available power and computing resources and those heavily reliant on future capacity buildout. Utilities, power grid equipment, natural gas power generation, data center infrastructure, and high-speed optical communications companies may continue to benefit, but project approvals, financing conditions, and energy supply will dictate the actual pace of revenue realization.

Oil Prices and Inflation May Influence Fed Policy Again

Energy prices remain another key variable following the election. Higher oil prices not only directly improve profits for energy companies, but could also push up transportation, manufacturing, and household costs, making the disinflation process more convoluted.

If inflation reignites, the Federal Reserve could delay rate cuts or maintain higher policy rates, putting pressure on growth stock valuations as well as rate-sensitive sectors such as real estate and consumer spending. Conversely, if energy prices retreat and inflation continues to improve, Treasury yields may fall, providing support for tech stocks and other high-valuation assets.

Historically, the S&P 500 Index has typically shown strong performance in the six months following midterm elections. According to BlackRock data, the index has gained an average of 14.1% during this period since 1970, outperforming the 5.7% average return over the same period in non-midterm election years.

However, historical patterns do not guarantee that the current rally will repeat itself. While U.S. midterm elections resolve political outcome uncertainty, they cannot automatically address issues like high interest rates, rising oil prices, or inadequate returns on AI investments. After the election, whether U.S. stocks can sustain their rally will ultimately depend on whether corporate earnings deliver, bond yields retreat, and massive AI capital expenditures translate into steady cash flows.