In response, Warren, currently a 2020 Democratic front-runner who has run a campaign vowing to heavily tax billionaires, sarcastically said the revelation “shocked” her and urged both billionaires to use her Ultra-Millionaire Tax calculator to find out how much they would owe under her plan.

The senator added: “Fortunately, they can both use my calculator to find out exactly how much they’d have to chip in under my #TwoCentWealthTax.”

Months after their reported call, Bloomberg appears to have changed his mind. Although he has not officially announced a bid for the 2020 presidency, Bloomberg rattled the Democratic presidential field after filing paperwork to enter the 2020 primary in Alabama on Friday.

Amid reports predicting his run for the Democratic Party’s presidential nomination during the week, Jon Cooper, a Democratic fundraiser, told The Washington Post that Bloomberg was motivated to run because he “obviously fears that Warren or Sanders might prevail in the primary and then end up losing to Trump.” “For those more centrist Democrats who share that concern, Bloomberg’s entry into the race could offer a belt-and-suspenders approach,” he added.

Warren playfully welcomed the billionaire to the race on Thursday by telling him how much tax he would pay under her plan. According to the Calculator for Billionaires, Bloomberg would owe roughly $3.08 billion next year if Warren is elected and her policy is enacted as his net worth is listed at around $52 billion.

Her digs at Bloomberg and Bezos came as her proposed tax plan has received pushback from other billionaires, including Microsoft co-founder Bill Gates. “I’ve paid over $10 billion in taxes,” Gates said at The New York Times’ DealBook Conference on Wednesday. “If I had to pay $20 billion, it’s fine. But when you say I should pay $100 billion, then I’m starting to do a little math about what I have left over.”