The GOP tax bill could boost the highest-earning Americans' incomes while hurting low earners, according to findings from nonpartisan research groups.

The greatest benefits would go to high-income households, while low-income families would see a much more modest boost, analyses show.

The Republican tax bill proposal is sparking intense debate as it moves through the House. While Republicans tout its benefits for taxpayers and businesses, Democrats criticize it as a boon for the wealthy.