Sen. Bernie Sanders (I-Vt.) announced Tuesday that he would be releasing 10 years’ worth of tax returns before Tax Day, when 2019 tax filings are due, arrives next week.

In an interview with The New York Times, Sanders, a strong contender for the 2020 Democratic presidential nomination, suggested that his tax returns would show that he is a millionaire. During his last presidential bid in 2016 and throughout his career, Sanders has criticized other politicians, especially President Donald Trump, for accepting money from big corporations and the ultra-rich.

“I wrote a best-selling book,” Sanders told the Times. “If you write a best-selling book, you can be a millionaire, too.”

Sanders also noted to the paper that he was not a “billionaire” who had “investments in Saudi Arabia,” like he says Trump does.

Sander’s announcement comes months after he confirmed he was running in the 2020 presidential election, which drew attention to whether the senator would release his own tax returns. Sanders often calls on Trump to release his tax returns and fiercely criticized the president for not releasing them after he was elected.