Paypal has told former English Defence League leader Tommy Robinson it will no longer process payments on his behalf, the BBC understands.
The payments network is believed to have told Mr Robinson he had violated its terms and conditions.
It said Paypal could not be used to promote hate, violence or discrimination.
Online petitions calling on finance firms to sever links with him have gained thousands of signatures.
In a statement, Paypal said it could not comment on individual customers but added that it regularly reviewed accounts to ensure their use aligned with its acceptable use policy.
Paypal added: "We do not take decisions like these lightly, and we work hard to be rigorous and fair-minded when reviewing PayPal accounts.
"Striking the necessary balance between upholding free expression and open dialogue and protecting principles of tolerance, diversity and respect for all people is a challenge that many companies are grappling with today."
In September, Paypal stopped processing payments for conspiracy theory site Infowars for promoting "hate and intolerance".
In May, Mr Robinson was jailed for contempt of court. The 13-month sentence sparked a series of #freetommy protests and a conviction which was later quashed after procedural concerns.