A man uses a Bitcoin ATM in Hong Kong. (AP Photo/Kin Cheung, File).

INTERNATIONAL – Coinbase, one of the largest US cryptocurrency exchanges, said Adam White, head of the institutional platform group and its fifth employee, is leaving the company.

White’s exit comes at a pivotal time for the San Francisco-based startup as it seeks to lock in large clients like hedge funds and other institutional customers after becoming a leading exchange for retail investors.

He was most recently the vice president and general manager of the institutional business. White declined to comment for this story.

“While we’re extremely sad to see him go, we’re also confident in that group’s ability to keep executing on the vision that he laid out to be the most trusted venue for institutional investors to trade cryptocurrencies,” a spokesman said in an email.

Yesterday, the firm announced that Jonathan Kellner, the former chief executive officer of Instinet, is joining as a managing director of its institutional business, taking over much of White’s coverage.

White joined Coinbase in 2013 when the founders were still working out of a one-bedroom apartment and Bitcoin was trading around $200. The biggest cryptocurrency peaked at almost $20,000 in December and has recently been trading around $6,500.

“Over the past five years, Adam helped us build our exchange business into the largest US-based crypto-trading venue, and was integral to growing Coinbase’s global presence and scaling our culture to multiple offices,” Coinbase CEO Brian Armstrong said in an email.

Prior to that, White served in the US Air Force and was a consultant at Bain & Co. He has an MBA from Harvard Business School.