The merger of BDO and Moore Stephens pushed the newly-combined firm into third place, overtaking Deloitte while EY remained in fifth position, according to the latest from Adviser Rankings.
PKF Littlejohn has moved up to eighth place in overall clients following its Welbeck Associates tie-up.
PwC has also regained its lead among the FTSE 100. For the first time since 2005, it was knocked off top spot in Q4 2018 by KPMG. PwC has now recaptured the position, adding Hikma Pharmaceuticals and Hiscox. However, it lost the lucrative contact of Vodafone, as the telecommunications company replaced it with EY after a firm that PwC was administrating considered legal action.
In the AIM market BDO doubled its advantage over KPMG from 26 to 52 clients.
KPMG revealed in November that it had has decided to stop performing non-audit work for FTSE 350 clients. The decision was aimed at restoring public trust in the audit sector following a number of recent scandals, including the collapse of Carillion and BHS.