US stock futures inched lower as investors digested President Donald Trump's announcement of 25% tariffs on global steel and aluminum imports. Trump imposed 25% tariffs on all steel and aluminum imports on Monday night.

But perhaps nothing has been more influential for the stock market over the last three months than Donald Trump's election night victory. During Trump's first term in the White House, the Dow Jones, S&P 500, and Nasdaq Composite respectively rose by 57%, 70%, and 142%.

Stock prices have risen sharply in recent years, but President Trump's new tariffs are causing investor concern. A 25% duty on imports from Canada and Mexico, and a 10% tariff on goods from China, might hurt companies' profitability and competitiveness.