Groups are made up of firms with financial links, where each firm occupies a specific place in the structure. A comparison of the Financial Links Survey (LIFI) with the DADS panel of annual payroll declarations by firms shows and quantifies the mobility of group employees in France from 1991 to 1999. This mobility can be placed in the context of an analysis of internal job mar-kets: the internal market for a group employee is the market within the company and within the group (mobil-ity between firms of the same group). We observe that this internal market is made up mainly of geographically close firms (in the same département) and structurally similar firms in the group. This finding holds regardless of the line of business and company size. However, the role of size is non-linear (it can be represented by a U curve).