• The US tariff on imported steel and aluminum doubles from 25% to 50% effective June 4.
• Canada and Mexico, major steel exporters to the US, are significantly affected by the tariff increase.
• Trading partners have been asked to submit their best proposals to avoid additional tariffs by July 8.

The U.S. tariff rate on most imported steel and aluminum has doubled effective June 4, rising from 25% to 50%. This increase comes as President Donald Trump intensifies a global trade war and expects trading partners to deliver their "best offer" to mitigate further punitive import tax rates that may take effect in early July, according to Reuters, The Jakarta Post, and Channel News Asia.

Trump signed an executive proclamation shortly before the tariff increase, which will apply to all trading partners except the United Kingdom. The UK, having established a preliminary trade agreement with the U.S., will see its steel and aluminum tariffs remain at 25% until at least July 9, according to Reuters and The Jakarta Post.

The increase disproportionately impacts the U.S.'s closest trading partners, particularly Canada and Mexico, who rank first and third, respectively, in steel shipment volumes to the U.S. Both countries export significant quantities of aluminum as well, making them particularly vulnerable to the new tariffs. Canada is notably the top aluminum exporter to the U.S., with its volumes far exceeding those of other countries, according to Reuters, The Jakarta Post, and Channel News Asia.

The rising tariff rates have jolted the market for metals, particularly aluminum, where price premiums have more than doubled this year. With domestic production capacities unable to rapidly meet the increased demand, import volumes may face limitations unless the price hikes negatively impact demand, as stated by Reuters and The Jakarta Post.

Wednesday also marks the deadline for trading partners to submit their best proposals aimed at dodging hefty tariffs projected for July 8 under Trump's "Liberation Day." The U.S. Trade Representative has communicated with multiple countries since announcing a pause on broader tariffs on April 9, yet only the U.K. has finalized a deal, according to Reuters, The Jakarta Post, and Channel News Asia.

White House officials are eager to secure more agreements before the deadline and have requested comprehensive proposals from trading partners addressing tariff and quota offers and commitments on digital trade and economic security. The proposals are expected to clarify what tariff rates countries may anticipate following the expiration of the 90-day pause on July 8, according to Reuters, The Jakarta Post, and Channel News Asia.