Amazon is one of the world's most valuable companies, valued at nearly $800 billion, and the e-commerce giant pulled in $232.9 billion in global revenue in 2018.

And yet, Amazon's federal tax bill this year: $0. For the second year in a row.

In fact, Amazon is actually getting a federal tax refund of $129 million this year, due in part to a combination of tax credits and deductions. This is despite the fact that Amazon nearly doubled its taxable income in 2018 to $11.2 billion, from $5.6 billion a year earlier.

In other words, Amazon is basically paying a -1 percent federal income tax rate this year after reportedly paying a federal rate of more than 11 percent between 2011 and 2016, according to The Week.

Sen. Bernie Sanders, I-Vt., who has criticized Amazon in the past for not paying higher federal taxes, took to Twitter on Thursday to point out that any Amazon Prime member paid more for that program's annual fee ($119) than the company paid in federal taxes.

BERNIETWEET

Prime has 100 million subscribers.

"Amazon pays all the taxes we are required to pay in the U.S. and every country where we operate, including paying $2.6 billion in corporate tax and reporting $3.4 billion in tax expense over the last three years," an Amazon spokesperson said in a statement provided to CNBC Make It.

Amazon reported its sizable federal refund in a recent corporate filing for the company's fourth-quarter earnings report. However, Amazon also notes in that filing that it will pay $756 million in total taxes this year, between state and international taxes.

A report this week from the Institute on Taxation and Economic Policy, or ITEP, a nonpartisan and nonprofit tax policy think tank, pointed out the fact that Amazon will not pay federal taxes for the second year in a row. In fact, last year, Amazon received an even larger refund, getting $137 million from the federal government.

One reason for Amazon's nonexistent federal tax bill is the Tax Cuts and Jobs Act that Congress enacted in 2017, which lowered the statutory corporate tax rate from 35 percent to 21 percent. In addition to the lower tax rates for corporations, the new tax law also "failed to ... close a slew of tax loopholes that allow profitable companies to routinely avoid paying federal and state income taxes on almost half of their profits," ITEP senior fellow Matthew Gardner wrote in a report on Wednesday.