We equip the polytope of n × n Markov matrices with the normalized trace of the Lebesgue measure of Rn 2 . This probability space provides random Markov matrices, with i.i.d. rows following the Dirichlet distribution of mean (1/n, . . . , 1/n). We show that ifM is such a randommatrix, then the empirical distribution built from the singular values of √ nM tends as n → ∞ to a Wigner quarter–circl...