By BLOOMBERG

PORTLAND • Facebook Inc executive David Marcus resigned from Coinbase Inc’s board, a sign the social network operator is pushing ahead with its own blockchain work.

Marcus quit last Friday, citing a new group he oversees at Facebook that’s exploring potential blockchain uses. “I’ve decided it was appropriate for me to resign from the Coinbase board,” he said in a statement. Coin- Desk, a blockchain news website, earlier reported the move.

While Facebook is yet to announce how it intends to harness blockchain, some analysts believe the company will follow in the footsteps of other players and issue its own cryptocurrency or token. If that happens, a board seat at Coinbase could be viewed as a conflict of interest, as Marcus could lobby the exchange to list a Facebook token, according to Lucas Nuzzi, director of technology research at Digital Asset Research.

“Many in the community were aware Facebook was expanding their efforts in this area,” Nuzzi wrote in an email.

Marcus announced in May that he was leaving his position as head of Facebook Messenger to focus on exploring the use of blockchain.

A few months prior, Facebook CEO Mark Zuckerberg said he was learning about encryption and cryptocurrency.

Under Marcus’ leadership, Messenger monthly user numbers jumped from 300 million to more than one billion, and the service added features like video chat, peer-to-peer payments and games, and opened up to developers.