In recent years, mergers, acquisitions and organic growth have meant that some of the largest and most complex financial groups have come to transcend national boundaries and traditionally defined business-lines. As a result, they have become a potential channel for the cross-border and cross-market transmission of financial shocks. This paper analyses the degree of comovement in the equity prices of a selected group of large complex financial institutions (LCFIs), and assesses the extent to which movements are driven by common factors. A relatively high degree of commonality is found for most LCFIs although there are still noticeable divisions between sub-groups of LCFIs, both according to geography and to a lesser extent primary business-line.