By Mrinalika Roy

June 3 (Reuters) - U.S. President Donald Trump's increased tariffs on imported steel and aluminum - key materials used in industries ranging from construction to packaging - kicked in on Wednesday, pushing duties to 50% from 25% previously.

While the tariffs are aimed at encouraging investment in domestic production, they have already fuelled higher costs for steel and aluminum consumers, while undermining manufacturing.

Given limited capacity to ramp up domestic output, U.S. import volumes are likely to be unaffected unless the price increases undercut demand, putting the spotlight on firms reliant on these shipments.

Here is a breakdown of the imports of both metals into the U.S. and the firms that ship them:

ALUMINUM

About half of all aluminum used in the U.S. is imported, with the vast majority coming from Canada, which exported 3.2 million tons of the metal to the country last year.

In 2024, total U.S. imports of aluminum articles were valued at $27.4 billion, according to data from the Observatory of Economic Complexity $(OEC)$, with Canada, China and Mexico the top three suppliers.

Data from the Aluminum Association shows that transportation, packaging, construction, electrical and consumer durables sectors import the most amount of aluminum by volumes.

According to U.S. CBP Bill of Lading data and shared by OEC, these firms were the top importers in 2024:

ES Windows LLC: A leading importer of aluminum products for architectural applications like windows and facades. It accounted for 18.4% of shipments

Netherlands-headquartered IKEA Group: Designs and sells ready-to-assemble furniture, home accessories and kitchen appliances. It accounted for 6.34% of shipments.

Global automotive manufacturer Nissan, discount retail chain Dollarama and disposable beverage and food supplies firm Lollicup: Each accounted for over 3% of total aluminum shipments last year.

Other major importers were Costco, Samsung, and Boeing.

STEEL

About a quarter of all steel used in the U.S. is imported, the bulk of it from neighbours Mexico and Canada.

In 2024, total U.S. imports of iron and steel articles were valued at $49.7 billion, according to data from OEC, with China, Mexico, and Canada being the top suppliers.

According to U.S. CBP Bill of Lading data and shared by OEC, these were the top importing companies of 2024:

Iron & Steel Articles:

IKEA accounted for 5.85% of total imports.

SIGMA Corp accounted for 3.94%

Stelfast, which makes industrial fasteners like bolts and nuts etc, made up 3.32% of shipments.

CrimsonLogic, a global technology firm, accounted for 3.21% of shipments.

Other notable companies include German technology firm ZF Friedrichshafen, Continental Materials, Stihl and Cosentino.

Basic Iron & Steel

Electronics manufacturing company TPV Tech accounted for 18.9% of shipments

Valbruna Stainless accounted for 12.8%

Brose Mechatronic Systems accounted for 5.89%

Multinational engineering and technology company Robert Bosch made up 8.89% of shipments

(Reporting by Mrinalika Roy in Bengaluru; Editing by Anil D'Silva)

((mrinalika.roy@thomsonreuters.com;))