E-commerce giant Amazon is under fire this week from Democratic presidential frontrunners Joe Biden and Bernie Sanders for its tax practices and a new Amazon Prime credit card for those with bad or no credit.

On Thursday, Biden posted on Twitter how Amazon pays a "lower tax rate than teachers and firefighters."

The New York Times in April noted how Amazon paid no taxes in 2018, citing a study from the left-leaning Institute on Taxation and Economic Policy. The study showed the company actually paid a -1.2% in taxes due to a $129 million tax rebate. 

The Bellevue, Washington-based company has benefited from The Tax Cuts and Jobs Act of 2017, which cut federal tax rates across the board and also expanded tax credits and rebates which affected some businesses and corporations.

Amazon responded that it paid $2.6 billion in corporate taxes since 2016. The company inferred that Biden's complaint is toward the country's tax code, not Amazon. 

Sen. Bernie Sanders of Vermont, a longtime critic of Amazon, also used Twitter on Thursday to lash out at the company for introducing a new credit card as a part of its Prime service for consumers with bad or no credit. Sanders criticized the card for having a 28% interest rate, which he said, "makes the poor even poorer." Sanders and Rep. Alexandria Ocasio-Cortez of New York have introduced legislation capping credit card rates across the country at 15%.

Amazon's business practices have drawn increased scrutiny, particularly by the progressive wing of the Democratic party.

Earlier this year, Amazon mulled moving its second headquarters to the New York City borough of Queens. The move was criticized by Ocasio-Cortez and Massachusetts Sen. Elizabeth Warren, who believed the headquarters would price locals out of their neighborhood. The backlash prompted Amazon to scrap the New York plans but remain in Northern Virginia.