Bruno de Finetti (13 June 1906 – 20 July 1985) was an Italian probabilist statistician and actuary, noted for the "operational subjective" conception of probability.

After graduation, he worked as an actuary and a statistician at Istituto Nazionale di Statistica (National Institute of Statistics) in Rome and, from 1931, the Trieste insurance company Assicurazioni Generali.

In 1936 he won a competition for Chair of Financial Mathematics and Statistics, but was not nominated due to a fascist law barring access to unmarried candidates;[2] he was appointed as ordinary professor at the University of Trieste only in 1950.

He published extensively (17 papers in 1930 alone, according to Lindley) and acquired an international reputation in the small world of probability mathematicians.

He also reasoned about the connection of economics and probability, and thought that guiding principles to be Paretian optimum further inspired by "fairness" criteria.

De Finetti emphasized a predictive inference approach to statistics; he proposed a thought experiment along the following lines (described in greater detail at coherence): You must set the price of a promise to pay $1 if there was life on Mars 1 billion years ago, and $0 if there was not, and tomorrow the answer will be revealed.

The 1974 English translation of his book is credited with reviving interest in predictive inference in the Anglophone world and bringing the idea of exchangeability to its attention.