Donald Trump's niece, Mary Trump, has suggested the economy is in such a bad state under the president's administration it's "dragging" businesses down.

Her claim comes as Costco file a lawsuit against the Trump administration, seeking a refund on tariffs. Costco's lawsuit urges the federal trade court to declare Trump's 'emergency' tariffs illegal, an authority the president says he has under the International Emergency Economic Powers Act (IEEPA).

Mary Trump has since suggested the state of the economy under Trump's administration goes against his election campaign promise to "boost American businesses".

She said, "Throughout the 2024 presidential campaign, Donald promised to boost American businesses, but he was lying. Shock. Instead, Donald's policies are dragging American companies down, so much so that a number of them are taking him to court."

Trump's "reciprocal tariffs" levy billions of dollars in taxes on Americans who import from practically any foreign country, based on calculations of the U.S. trade balance with those countries — even if a trade surplus or deficit exists for reasons other than statutory trade laws.

But Mary Trump says the tariff plan put in place by the president has been a "disaster from the beginning". She also questioned just how much money had actually been made by the tariffs since they were introduced in February this year.

She said, "The federal government has allegedly taken in $90 billion as the direct results of the tariffs that Donald imposed on essentially every single one of our trading partners. This has been disastrous for the economy and I don't see any reason to believe that that much money has been generated by the tariffs."

"But then the question remains, if indeed that money has been taken in, at what cost to American businesses? Clearly businesses like Costco and Amazon and Best Buy and Walmart are stuck with an increasingly high price tag for goods they're importing into the United States."

"Are those higher costs all being passed on to the American consumer, we know that everything is getting more expensive for Americans. Or are some companies swallowing some of those losses so they don't have to raise the price of their goods beyond the reach of their customer base? Either way, companies in America are suffering and losing money regardless of whether or not the government is 'making' it."