The stock-trading startup Robinhood has hired a chief financial officer – who spent 20 years at Amazon – in a move that helps push Robinhood toward an initial public offering.

Jason Warnick, who joined Amazon in 1999, is decamping to Robinhood, the startup told Recode on Monday.

Financial technology, or fintech, companies will sometimes hire CFOs even before they are thinking about an IPO, given that their core businesses are finance-related, but Robinhood’s leadership has said that the company is preparing for a listing in the “Medium- to long-term.” A CFO hire is considered essential for any company to make sure its books are straight before hiring bankers to guide the IPO process.

Robinhood hasn’t yet taken the other necessary step of adding independent members to its board of directors.

“I’m thrilled to join the amazing team at Robinhood and look forward to advancing our mission to democratize America’s financial system,” Warnick said in a statement.

Robinhood, which claims to have six million customers, is one of the most promising fintech startups in the U.S., valued at $5.6 billion earlier this year.

Legacy incumbents like JPMorgan Chase are increasingly gunning for that same customer – and maybe there is a world in which one of them prevents a Robinhood IPO by buying it.