Turin 1846-Milan 1922. A banker, from a Jewish family in Turin, in Milan in 1869 with his father Lazzaro and brother Alberto. Aged 23, in 1869 he and his brothers Lazzaro and Angelo set up the Donati-Jarach company of exchange dealers and bank commission agents in Via Santa Margherita, near Piazza della Scala. The bank rode out the difficult years 1873-1874 and the banking crisis of 1893 by diversifying risks. In 1899 the brothers Gustavo and Alberto Weill-Schott decided to incorporate Donati Jarach into their new company, Società Bancaria Milanese, forming an alliance with a group of Milanese bankers and industrialists. After the sale, the Jarach brothers worked in the Società Bancaria Milanese, on the board of directors as shareholders from 1899 to 1901. In 1913 he entered the council of regency of the Bank of Italy.