Sunderland have been fined £100,000 by the Football Association for breaking Football Agents Regulations.
The incident which led to the fine by English football's governing body has not been released by the organisation or the Black Cats, who admitted to the violation.
Agent Abu Mahfuz has also been sanctioned by the FA for the same matter which has resulted in a two-year suspension of his licence, with six months to be served from the end of this month.
Mahfuz was also fined £500 after an Independent Regulatory Commission hearing proved his breach of the regulations despite his denial. Both Sunderland and Mahfuz have the opportunity to appeal the punishment by the FA.