Last year, as business prospects ramped up in Brazil, Latin America's biggest economy, Paul Hastings took a hard look at its practice there.

The AmLaw 100 firm lacked critical mass to be truly competitive in the market, having lost two of the three Brazil-based lawyers that debuted its South American outpost in 2016. So Paul Hastings approached Jonathan Kellner, head of Shearman & Sterling's São Paulo office and a longtime resident of Brazil, with an offer to switch alliances.