The sanction was passed down following an Independent Regulatory Commission hearing, which also sees agent Abu Mahfuz handed a two-year suspension, 18 months of which are suspended.
Mahfuz was also fined £500 and warned as to his future conduct, but denied breaching the Football Association's (FA) Football Agents Regulations.
The full FA statement read: "Following an Independent Regulatory Commission hearing, Sunderland have been fined £100,000 and warned as to their future conduct after the club admitted breaching The FA’s Football Agents Regulations.
"In relation to the same matter, Abu Mahfuz has had his Agent licence suspended for two years with six months to be served starting from May 21 2014. The remaining 18 months is to be suspended and will be invoked upon a proven breach of The FA’s Agents Regulations during that period.
"Mr Mahfuz, who was also fined £500 and warned as to his future conduct, had denied breaching The FA’s Football Agents Regulations, however, the charge was found proven following an Independent Regulatory Commission hearing.
"The above sanctions are subject to any appeal."
