Rathbones has won the £43m race to buy Jupiter's private client arm and is also to purchase part of Tilney IM"s private client business in a separate £14m deal.
Psigma Investment Management has hired Rathbones investment director Tim Wishart to lead its expansion in Scotland.
Rathbone Brothers' total funds under management rose 22% by the end of 2013 to £22bn, according to latest results.
Rathbone Brothers is reviewing the latest judgement in its ongoing Jersey trust legal dispute after the latest ruling.
Rathbones has seen its funds under management swell to more than £20bn, helped by its recent acquisition in the private client space.
Rathbone Brothers' subsidiary, Rathbone Investment Management, has acquired wealth management firm RM Walkden & Company following a stream of hires.
A marked rise in net fee income in its investment management division helped Rathbone Brothers post a 30% increase in profits in 2011.
Rathbones is preparing to add a third fund to its multi-asset range, to be run by investment director David Coombs.