A bank spokesman said it "periodically" reviews all its marketing suppliers. It is three years since the last review, which was understood to have been a closed process.
ID Comms is advising Barclays on the competitive pitch. Maxus took the UK business in 2011 from Walker Media, which was then owned by M&C Saatchi but has since become majority-owned by Publicis Groupe and rebranded Blue 449.
Barclays has been criticised in recent years over issues such as the Libor-fixing scandal. Jes Staley became its third chief executive in six years when he started in December 2015.
Richard French, Barclays’ head of brand, took charge of marketing after a trio of high-ranking marketers, David Wheldon, Sara Bennison and Michelle McEttrick, departed in 2014 and 2015.
The bank has pulled back from some high-level sponsorships, such as the English Premier League and the London "Boris" bike scheme.
Barclays is also restructuring to "ring-fence" its UK bank as part of new, tougher banking regulations.