Company: this archive includes a series of data relative to firms (year of foundation, sector of activity^[1], location, share capital and paid-up capital) for 9 benchmark years (1911, 1913, 1921, 1927, 1936, 1952, 1960, 1972 and 1983).^[2] On the basis of the information gathered from the brief company profiles found in the source, each company has a code, allowing us to track company continuity even in cases of changes in company name. This task has required a big effort since it is not easy, due to the complexity of merger and acquisition processes, to assign the continuity of an activity to a firm. However, this information is essential because it allows both the possibility to follow a company along its history and to make reliable empirical analysis on firms’ demography.

_{[1] The sectors of activity were standardised on the basis of the ATECO-ISTAT 1991 classification by section, subsection, division and group. The firms were classified according to the main sector of activity.}

_{[2] The reference years are those for which the source contains data and they do not always correspond to the year in which the volume was published or to the year stated in the title.}