Washington DC: Customs officials across the US began collecting a 10% tariff on all imports from a wide range of countries on Saturday, marking the implementation of President Donald Trump's sweeping trade policy, according to a Reuters report.

The tariff, described as a “baseline” duty, came into force at ports, airports and customs warehouses at 12:01 a.m. ET, signalling a firm departure from the post-World War II consensus on negotiated tariff rates.

“This is the single biggest trade action of our lifetime,” said Kelly Ann Shaw, a trade lawyer at Hogan Lovells and former White House trade adviser during Trump’s first term, according to the Reuters report.

Speaking at a Brookings Institution event, Shaw noted that the tariffs could evolve as nations negotiate better rates. “But this is huge. This is a pretty seismic and significant shift in the way that we trade with every country on earth,” she said, the report added.

Shockwaves across global markets

Trump’s announcement on Wednesday rattled global stock markets, wiping out $5 trillion in S&P 500 company value by Friday—the steepest two-day drop on record.

Oil and commodity prices tumbled, and investors rushed toward the safety of government bonds.

The first group of countries hit with the 10% tariff includes Australia, the United Kingdom, Colombia, Argentina, Egypt and Saudi Arabia.

While most goods arriving from Saturday onwards are subject to the new duty, the US Customs and Border Protection bulletin provided a 51-day grace period for cargo already en route before the cutoff.

These shipments must land in the US by 12:01 a.m. ET on May 27 to qualify for the exemption.

Steeper tariffs incoming midweek

On Wednesday, Trump’s “reciprocal” tariff regime—with rates ranging from 11% to 50%—will take effect.

Imports from the European Union will be subject to a 20% duty, while Chinese goods will face a 34% hike, pushing total tariffs on China to 54%.

Vietnam, which gained from earlier supply chain shifts away from China, is slated to be hit with a 46% levy.

However, the country has agreed to open talks with the US on a possible deal.

Exemptions and exclusions

Canada and Mexico have been spared from this round of duties, although both are still under a 25% levy linked to the US fentanyl crisis for products not meeting USMCA rules.

Goods covered by previous national security tariffs—such as steel, aluminum, and automobile components—are also excluded from the latest hike.

Additionally, the Trump administration unveiled over 1,000 product categories exempted from the new tariffs.

These items, amounting to $645 billion in 2024 import value, include crude oil, petroleum products, pharmaceuticals, uranium, titanium, semiconductors, copper and lumber.

However, aside from energy imports, many of these sectors are under review for potential national security-related tariffs in the future.