For being one of the richest people in the U.S., Amazon CEO Jeff Bezos isn’t the best at keeping up with his fellow billionaires when it comes to philanthropy.

He donated $98.5 million to dozens of groups focused on helping the homeless last week, but critics love to pile on the Forbes 400 front-runner, who is worth around $114 billion, according to the 2019 iteration of the list. Bloomberg estimates the Amazon CEO is actually only worth $109 billion, which is tied with Microsoft founder Bill Gates.

U.K. Labour Party leader Jeremy Corbyn is the latest to call Bezos out after last week’s paltry (when compared to his wealth) donation. In a tweet Sunday, Corbyn did the math and figured Bezos’ contribution was “0.09%” of his net worth. In a final jab, Corbyn told the Amazon CEO, “just pay your taxes.”

Corbyn’s demand likely has something to do with the fact that Amazon did not pay a cent in federal taxes in 2018, and this was after posting profits of more than $11 billion before taxes.

Bezos has been called out in the past for his company’s shady tax tactic. In April, Bezos tried to challenge his retail competition to raise their minimum wages above Amazon’s $15 per hour. Walmart Executive Vice President of Corporate Affairs Dan Bartlett fired back with a snarky response on Twitter.

Bartlett’s tweet asked “how about paying your taxes?”

Another recent study by a University of Cal Berkeley economist found that the individuals on the Forbes 400 list managed to double their wealth over the last decade, while also paying less in taxes.

And as far as Bezos’ philanthropic efforts? Last week’s $98.5 million contribution was part of his Bezos Day One Fund, which is a $2 billion fund Bezos launched in September 2018. But critics have called into question how the fund would actually be used to help, and why it only amounts to less than 2% of the Amazon CEO’s worth. There’s also no timetable for how long it will take Bezos to reach the $2 billion goal, according to CNBC.

Bezos is lagging his fellow billionaires, too. He ranked 23rd on Forbes’ 2018 list of charitable givers. His 2018 contributions totaled $131 million. Fellow uber-rich titans Bill and Melinda Gates gave $2.6 billion, and investor extraordinaire Warren Buffett donated a whopping $3.4 billion.

Gates and Buffett also are founding members of the Giving Pledge, signed so far by 204 billionaires — including Bezos’ now former wife, MacKenzie — which is a group of fellow billionaire who have agreed to give away most of their fortunes when they die. The Giving Pledge, founded in 2010, is expected to have raised about $600 billion in charitable contributions by 2022.

It looks like you’ve got some catching up to do, Bezos.