A report by CNN has accused the club of breaking regulations by using two unlicensed agents, Daniel Villagran and Oscar Bianco, during the course of completing the transfer last summer.
Villagran and Bianco claim they have not been paid for their alleged part in the deal that saw Yacob move to the Hawthorns on a free transfer from Racing Club in July 2012.
A breach of the rules governing unlicensed agents can be punished through fines or even points deductions, but West Brom insist they have done nothing wrong.
A club statement said: "As with all of our transfer dealings, the negotiation process regarding the signing of Claudio Yacob complied fully with all FIFA and FA rules and regulations.
"All negotiations were conducted and concluded directly with a FIFA-registered agent."
The CNN report claims Villagran and Bianco had been in England with Yacob for talks over the move, and also flew to Naples with the player to arrange an Italian passport, meaning he would not need a work permit to play in England. But it asserts another licensed agent, Xabier de Beristain Humphrey, was named on official documentation.
The report also claims the pair's laywer, Ariel Reck, sent a letter to the Football Association in November 2012, asking it to look at the alleged involvement of unlicensed agents.
The FA refused to confirm or deny whether it was investigating the deal when contacted by Press Association Sport.