The genealogy of the US national firm is becoming more and more complex. Ever mindful of the need to grow in line with the needs and expectations of clients, mega-mergers between firms have been driven by an apparent need to acquire greater depth of expertise and geographical reach.

This consolidation among the US national firms is driven by a number of factors, but one trend identified by a number of national firm managing partners who Legal Week spoke to is the fact that clients are slimming down the number of firms with which they maintain close relationships.