The Dutch goalkeeper was signed by Tottenham from the Swans in the summer of 2014 but Utrecht claim they never received the 30% sell-on fee that was written into his contract when he joined the Welsh club in August 2011.
Utrecht have taken up the matter with the Court of Arbitration for Sport (CAS) as they strive to receive the compensation they feel they are owed.
Swansea claim that the transfer to Spurs was a free as it was made in association with the Ben Davies-Gylfi Sigurdsson deal but Utrecht have questioned that as they believe a Holland international who had two years remaining on his contract surely would have demanded a transfer fee.
Regarding the investigation, a Swansea spokesperson said: "The transfer of Michel Vorm was conducted and concluded correctly under Premier League rules.
"It was approved by the Premier League and also FIFA via their TMS (Transfer Matching System).
"While we have been in contact with Utrecht as a matter of courtesy, we will continue to conduct our business in the best interest of our football club and our supporters, and not based on the views of other clubs.
"Unlike some countries abroad, we do not have third party ownership of players in Britain. The club will not be commenting further on this matter."
A hearing will be held at the CAS in Lausanne, Switzerland on January 29, 2016.