Nucor shares are up 6% today after strong quarterly results that Chief Executive Leon Topalian credited to President Trump's aggressive use of tariffs, despite an uptick in steel imports.

"Vigorous enforcement of our trade laws is curtailing the flood of unfairly traded steel into the U.S. market," Topalian said during a conference call. He said strong demand for steel, however, is draining domestic stocks, leaving long waits for orders that are causing buyers to shop offshore even with a 50% tariff on imports.

Imports made up 16.4% of the U.S. flat-rolled steel market in the second quarter, up from 14.4% in the first quarter. Those were down from 22% in early 2025, however.

"If you asked me five years ago, would I take 16% overall imports into the U.S.? All freaking day long!" Topalian said.