MILAN (Reuters) -Prysmian shares rose as much as 4% on Wednesday on expectations the world's largest cable maker's large U.S. business could benefit from U.S. tariffs on copper, as it sources the metal locally and should be able to pass on higher prices to customers.

U.S. President Donald Trump on Tuesday said he would impose new levies, including a 50% tariff on imported copper, broadening a trade war that is rattling markets worldwide.

"We constantly monitor potential effects on metals coming from tariffs and as a result we align prices accordingly," a spokesman of Italy's Prysmian said.

Copper is a key element used in the production of a wide variety of cables including for power grids, construction, industrial uses and high-voltage transmission.

As a group, Milan-based Prysmian is the largest single buyer of copper worldwide, and the leader in the U.S. cable sector.

The Italian firm has the United States as its largest market, where last year it acquired Texas-based Encore Wire in a $4.2 billion deal.

"We highlight Prysmian as a relative tariff winner," analysts at Citi said in a note, pointing Prysmian's U.S. low-voltage business sources its raw copper from a Freeport mine in Arizona and operates its own copper rod mill in Texas rather than buying copper rod from suppliers.

"As such, its domestic, vertically integrated set-up in copper gives it a competitive edge compared to smaller players in our view," they said.

By 1000 GMT Prysmian shares were up 3.9%, among the best performers among Italy's blue chips.

Italian broker Equita said in a note tariffs should support copper prices and strengthen margins in the U.S. low voltage business, net of effects on demand.

The Prysmian spokesman said the company still needed to assess the final set-up of the new tariff scheme but it was well positioned thanks to its vertical integration in the copper space in the United States.

"Copper, and aluminium, are central to the energy objectives of the (U.S.) administration and we are committed to help support the development of local industrial reshoring, the development of AI through data centres and the strengthening of the U.S. power grid thanks to our leadership position in the market".