A bill that would lower taxes for the wealthiest Americans would hit a tax hike of $1,621 trillion over a decade, according to the American Conservative.
The group, which has been tracking tax hikes since before the November election, predicted the bill would hit $1 trillion by 2026.
The tax bill, however, has a number of caveats, including that it does not contain the tax cuts originally promised by President Trump.
The American Conservatives said that its numbers show the bill could increase taxes for middle-income Americans by $3.6 billion.
It said that a reduction of $3,600 in the top income tax rate could bring the total bill to $3 trillion.
According to the report, the bill includes a $25 billion tax break for the wealthy and a $50 billion tax cut for businesses.
The report also said the bill will raise taxes on millions of middle-class families.
The Congressional Budget Office, which is conducting a score of the bill, said the tax plan would increase taxes on a record 4.2 million middle- and low-income households, or 4.4 percent, which would result in a $30 billion tax hike for them.
It said the legislation would increase the top marginal tax rate from 35 percent to 39.6 percent, a rate that would increase by $1 million for the lowest- and middle-earners.
For middle- income earners, the top rate would increase to 39 percent.
For low- and moderate-income earners, it would go up to 39, and for high-income families it would increase from 37 to 39 as well.
Under the tax bill passed by the House on Wednesday, the richest 1 percent of Americans will pay an average of $7,500 a year, up from $4,400 under the current law.
If the bill is passed by Congress, it will take effect in 2021.