The odds, whose bet will resolve as "yes" if Durov is released from custody by August 31, has dropped to just 25% of being released, Polymarket data shows.
Punters had placed his chances at 50% when the bet was first created on Sunday, but it fell sharply after it became clear that the French authorities and judicial process would keep him in pre-trial detainment.
The basic idea of Polymarket is straightforward: if a user's prediction is correct, they earn money. If it's incorrect, users lose the amount they wagered.
The underlying mechanics appear simple but have nuances. The price of a "share" in a prediction market typically ranges from $0.00 to $1, with its value reflecting the percentage chance of the outcome occurring, essentially representing the "odds."
Durov was arrested on the weekend as part of a preliminary police investigation by France’s National Anti-Fraud Office into allegedly allowing a wide range of crimes stemming from a lack of moderation on his platform and a lack of cooperation with the police.
The Russian-born French multi-national is accused of letting criminal activities go on undeterred on the app, allegations the platform dismissed as "absurd" on Sunday.
Durov holds citizenship in France, the UAE, Russia, and Saint Kitts and Nevis.
Under French law, he can be held for 96 hours, and then a judge will need to decide if he can be held for longer.
However, TF1, the French website that broke the news, noted that as Durov is a billionaire worth $15.5 billion, with a private jet and dual nationality, he is also a flight risk.
“Pavel Durov will end up in pretrial detention, that’s for sure,” TF1 quotes an unnamed investigator on the case.
The potential rap sheet is long, with the investigation including alleged links to facilitating terrorism, the sale of narcotics, stolen goods, fraud, and more.
Whether he remains in custody until his trial or not, Telegram has responded to the arrest to argue for his innocence, saying that Durov has “nothing to hide” and Telegram “abides by EU laws, including the Digital Services Act.”
“It is absurd to claim that a platform or its owner are responsible for abuse of that platform,” Telegram said in its statement.