Manchester City have failed in an initial bid to have the Court of Arbitration for Sport (Cas) halt Uefa's investigation into a possible breach of Financial Fair Play (FFP) rules.
City have been referred to Uefa's financial watchdog, the Club Financial Control Body (CFCB) and if found guilty could face a Champions League ban.
Cas said City's appeal was "inadmissible" at this stage because the CFCB has not yet determined what, if any, punishment would be applied if they were found guilty.
The club, who deny wrongdoing, had argued that Uefa did not have the authority to bring an FFP case against them.
Uefa launched an investigation after German newspaper Der Spiegel published leaked documents alleging City had inflated the value of a multimillion-pound sponsorship deal, misleading European football's governing body.
Reports alleged City deliberately misled Uefa so they could meet FFP rules requiring clubs to break even.
The FA Cup winners were fined £49m in 2014 for a previous breach of regulations.