In the world of betting, papal elections have not been immune. Pope Gregory XIV took drastic action against gambling on papal elections, establishing excommunication as the punishment. Leighton Vaughan Williams and David Paton dug into this strange tradition in the 2013 papal election, adding a unique spin to the betting history of conclaves, which has lasted at least 500 years. Insider trading, massive sums changing hands, and strict laws, including an excommunication risk, make betting on papal elections a contentious and intriguing subject, culminating in moments like Paddy Power’s record-breaking betting market during a conclave.
https://en.wikipedia.org/wiki/Gambling_on_papal_conclaves