Attorney general Michael Lauber said the “suspicious” cases had been reported by banks and that a “huge and complex” inquiry into football’s world body could take months if not years.
Officials said the 53 are individuals and companies and that each case could involve many more transactions.
“We note positively that banks in Switzerland did fulfil their duties to file suspicious activity reports,” he told a press conference.
“Partly in addition to the 104 banking relations already known to the authorities, banks announced 53 suspicious banking relations via the Anti-Money-Laundering-Framework of Switzerland,” he added.
Swiss authorities have set up a special task force to look into the World Cup bids — which went to Russia for 2018 and Qatar in 2022.
It is one of two major fraud investigations that have rocked FIFA.
US authorities last month charged 14 people in a separate bribery investigation.
Lauber said he “does not exclude” questioning FIFA boss Joseph Blatter or general secretary Jerome Valcke, although neither is currently under suspicion.
– Probe will take time –
He said nine terrabytes of data had been seized, including at FIFA’s Zurich headquarters and the probe would take time.
“The world of football needs to be patient… By its nature, this investigation will take more than the legendary ’90 minutes’,” that a football match takes, said Lauber, who has just been re-elected for a four-year mandate.