Mastercard, Visa, eBay and payments firm Stripe have pulled out of Facebook’s embattled cryptocurrency project, Libra.
Their move, first reported in the Financial Times , follows the withdrawal of PayPal, announced last week.
It represents a huge blow to the social network’s plans to launch what it envisions as a global currency.
The project has drawn heavy scrutiny from regulators and politicians, particularly in the US.
Facebook chief executive Mark Zuckerberg will appear before the House Committee on Financial Services on 23 October to discuss Libra and its planned roll-out.
Regulators have raised multiple concerns over Libra, including the risk it may be used for money laundering.
Mercado Pago, a payments firm serving mostly Latin America, also pulled out. It means of the six payments-related firms first involved in Libra, just one, PayU, remains. Netherlands-based PayU did not respond to the BBC's request for comment on Friday.
In a statement released on Friday, eBay said it “respected” the Libra project.
“However, eBay has made the decision to not move forward as a founding member. At this time, we are focused on rolling out eBay’s managed payments experience for our customers.”
A spokesperson for Stripe said the firm supported the aim of making global payments easier.
"Libra has this potential. We will follow its progress closely and remain open to working with the Libra Association at a later stage.”
A spokesperson for Visa said: "We will continue to evaluate and our ultimate decision will be determined by a number of factors, including the Association's ability to fully satisfy a...