Marc Yor (24 July 1949 – 9 January 2014) was a French mathematician well known for his work on stochastic processes, especially properties of semimartingales, Brownian motion and other Lévy processes, the Bessel processes, and their applications to mathematical finance.

Yor was a professor[1] at the Paris VI University in Paris, France, from 1981 until his death in 2014.

[citation needed] He was a recipient of several awards, including the Humboldt Prize,[2] the Montyon Prize,[3] and was awarded the Ordre National du Merite[3] by the French Republic.

He was a member[3] of the French Academy of Sciences.

His students include such notable mathematicians as Jean-Francois Le Gall[4] and Jean Bertoin.