Trump personally chose the 'mocked formula' used to determine tariffs: reporter

President Donald Trump personally selected the formula that the U.S. government will use to determine the percentage of reciprocal tariff to be implemented on a country, territory, or island, according to a Friday report.

The Washington Post's Jeff Stein wrote that numerous aides at the National Economic Council, Council of Economic Advisers, Commerce Department, and the Office of the United States Trade Representative confirmed the president made the decision himself.

"The now widely-mocked formula" was part of a weeks-long effort "crafting country-specific tariffs that took into account a broad range of tariff and non-tariff barriers," said Stein.

ALSO READ: 'We’ve made a mistake': Trump’s trade war sends GOP into frenzy

The report cited several sources who said that there were "more sophisticated approaches" that Trump could have picked.

"I can't confirm precisely who authored the one Trump picked, but it bears striking similarities to methods previously backed publicly by Peter Navarro, the ultra-trade hawk," Stein posted on X.

Trump promised Americans that the trade percentages would be reciprocal, a White House fact sheet from February confirmed.

“If they charge us, we charge them,’’ the president said in February while announcing a new wave of tariffs on steel and aluminum imports. “If they’re at 25, we’re at 25. If they’re at 10, we’re at 10. And if they’re much higher than 25, that’s what we are too.’’

On Thursday, Trump repeated that sentiment: "They charge us; we charge them. We charge them less. So, how can anyone be upset?"

But his tariff formula relied on a simplistic approach of dividing the U.S. trade deficit with a country by its exports to the U.S., rather than calculating actual tariff rates. The resulting numbers rattled global markets, disrupted supply chains, and threatened to escalate trade wars with key U.S. allies and trading partners.

Peter Draper, professor and executive director of the Institute for International Trade and international trade lecturer Vutha Hing, at the University of Adelaide, wrote for The Conversation that the Trump tariffs were not reciprocal as he indicated they would be.

The "Trump administration hasn’t directly matched specific foreign tariffs. Instead, they’ve opted for a crude formula based on bilateral trade deficits between the U.S. and each specific country. Those aren’t the same things," they explained.

The Dow Jones fell more than 1,000 points on Thursday and Friday, the Wall Street Journal confirmed.

Still, the concerns are inconsequential to Trump, one staffer told the Post.

“He’s at the peak of just not giving a f--- anymore,” the official who knew Trump’s thinking told the Post. “Bad news stories? Doesn’t give a f---. He’s going to do what he’s going to do. He’s going to do what he promised to do on the campaign trail.”

Read the full report here.