Between July 19 and July 25, Donald Trump's threats of military action against Iran and a broad new wave of tariffs dominated financial markets. Oil prices climbed as geopolitical risks intensified, while trade measures targeting dozens of economies raised fresh concerns about inflation, corporate costs, and the trajectory of interest rates.

Here are the five Trump-related developments that mattered most for markets this week.

1. Iran Threat Sends Oil Above $100

Trump threatened Iran with major military action following further Houthi attacks on commercial shipping, warning that Tehran could face consequences if the attacks continued. His remarks immediately heightened fears of disruption in the Red Sea and the Strait of Hormuz, both critical arteries for global oil and shipping. The Strait of Hormuz alone carries roughly 20% of the world's daily oil supply, making any disruption there a direct threat to global energy availability and pricing.

🇺🇸🇮🇷 Trump ordered the U.S. military to stand down from Iran strikes today, breaking a 13-day streak of daily attacks Why now: An Omani delegation arrived in Tehran hours earlier for talks on reopening the Strait of Hormuz. Two regional sources say progress has been made. A… pic.twitter.com/V9dsiyZwTh — Mario Nawfal (@MarioNawfal) July 25, 2026

Oil is back above $100, and gas is above $4. These numbers are brutal for inflation and Americans' pocketbooks. And there is no end in sight for their fundamental cause: Trump's war of choice in Iran. pic.twitter.com/LtTEpYrGjf — Steve Rattner (@SteveRattner) July 23, 2026

Brent crude briefly rose above $100 a barrel. Higher oil prices can increase transport and production costs, which may push inflation higher. That could delay interest rate cuts or compel central banks to maintain tighter monetary policy. The timing is particularly sensitive for the Federal Reserve, which has been weighing whether inflation has cooled enough to begin easing rates. Technology stocks and Bitcoin also faced pressure as bond yields climbed and investors reduced exposure to riskier assets.

2. Trump's Tariff Wall Gets Wider

Trump ordered new tariffs of 10% or 12.5% on goods from 60 economies. The affected markets include China, India, the European Union, Japan, and South Korea. The measures cover a large share of US trade and could raise costs for retailers, manufacturers, and companies dependent on imported components.

Businesses may pass some of those costs to consumers, which would keep inflation elevated and make it harder for the Federal Reserve to reduce interest rates.

TRUMP JUST IMPOSED NEW TARIFFS ON 60 COUNTRIES STARTING TODAY. The Supreme Court struck down Trump's original "Liberation Day" tariffs in February. In response, Trump imposed temporary 10% global tariffs as a placeholder. Those tariffs were set to expire today, and today's new… pic.twitter.com/eoc3EFbs37 — Bull Theory (@BullTheoryio) July 24, 2026

The Supreme Court's February ruling that struck down the original "Liberation Day" tariffs left a legal void that the administration moved quickly to fill, making this latest round a test of whether the revised approach can withstand further judicial scrutiny.

The tariffs could also hurt corporate profit margins. Consumer goods companies, automakers, and technology manufacturers face some of the highest risks.

3. Canada Becomes the Latest Trade Target

Trump announced additional 50% tariffs on approximately $20 billion of Canadian products. The affected goods include dairy, wine, furniture, cement, and sporting equipment. Energy and critical minerals received exemptions.

Nevertheless, the decision raised fears of retaliation from Canada and further disruption to North American supply chains. The measures add strain to a trading relationship governed by the USMCA, under which Canada and the U.S. exchange roughly $700 billion in goods annually. The Canadian dollar weakened during the week as trade uncertainty increased. US companies that import Canadian products may also face higher costs when the tariffs take effect in August.

🇺🇸🇨🇦 Trump dropped a HUGE bombshell on Canada! After they disinvited the U.S. from the Gordie Howe Bridge opening, he fired back hard: the original deal is DEAD. The U.S. is now taking 50% of the profits, and Canada can keep paying those big tariffs. He's not playing nice, by… pic.twitter.com/GAG7ZtIqDu — Mario Nawfal (@MarioNawfal) July 24, 2026

The dispute could reduce trade between two closely connected economies. It may also increase prices for construction materials and some consumer products.

4. Defence Firms Face a China Supply Chain Test

Trump signed an order tightening restrictions on foreign materials used by US defence contractors. Companies will face tougher rules when seeking permission to buy critical minerals or components from China and other restricted markets.

The order could benefit American rare-earth miners and metal processors. Shares in some domestic suppliers rose after the announcement. However, defence and aerospace companies may face higher costs during the transition period. China processes roughly 85–90% of the world's rare earth elements, materials essential to precision-guided munitions, fighter jet engines, night-vision equipment, and advanced semiconductors. Restructuring those supply chains is expected to take years, and supply shortages could delay production and increase government contract costs.

5. Aluminum Tariffs Get an Investment Clause

Trump introduced a new system linking aluminum tariff relief to investment in US production. Companies that build or expand American smelters may import a matching amount of aluminum at a reduced tariff rate.

The policy could support US aluminum producers and encourage new domestic investment. The U.S. currently operates only a handful of primary aluminum smelters, producing well under 20% of domestic demand, which makes import reliance a structural feature of the market. The investment clause could also create higher costs for businesses that do not qualify for the reduced rate. Automakers, construction companies, and beverage manufacturers use large amounts of aluminum, and any rise in metal prices could affect their margins and eventually reach consumers.

🇨🇦 Canada slapped 200-300% tariffs on American dairy. Called it protecting Canadian farmers. Americans called it what it was. Now imagine Trump wakes up tomorrow and hits Canada with 200-300% tariffs on everything we export. Lumber. Oil. Auto parts. Steel. Aluminum. The… — wealthmoose (@wealthmoose) July 24, 2026

Overall, Trump's actions this week placed oil, tariffs, and inflation back at the center of market attention. Investors will now watch whether the measures trigger retaliation, higher consumer prices, or a wider Middle East conflict.