Coinbase president and chief operating officer Asiff Hirji is leaving the cryptocurrency exchange, the company confirmed Friday.

Hirji joined the crypto unicorn in December 2017, joining after a stint at venture capital firm Andreessen Horowitz.

“We’re incredibly grateful for Asiff’s contributions over the past 18 months,” Brian Armstrong, co-founder and CEO of Coinbase, said in a statement. “His experience and mentorship helped guide Coinbase through an important chapter in its history. He joined at a critical time when both the company and crypto space were going through rapid growth, bringing his extensive experience to bear when it was most necessary.”

Hirji previously served as president and COO of TD Ameritrade.

Coinbase also announced Friday that Emilie Choi, the company’s vice president of business, data and international, would be taking over as chief operating officer. Choi presided over Coinbase’s $300 million Series E funding round last October, which valued the company at $8 billion.

The move comes following the recent departures of other C-suite executives at Coinbase. Chief technology officer Balaji Srinivasan left the firm earlier this month. Dan Romero, who worked as vice president of Coinbase’s international business, left in April.

According to a report by The Information, Tina Bhatnagar, Coinbase’s current vice president of operations and technology, is also expected to leave the company.

News of Hirji’s departure was first reported by Bloomberg’s Julie VerHage.

Emilie Choi speaks at Consensus 2019, image via Coinbase