Eulogy will work until next spring to promote the rebrand of around 1,000 branches to consumers. In May, Santander announced it was rebranding its three UK businesses Abbey, Alliance & Leicester and the savings division of Bradford & Bingley to Santander.
Although Eulogy would not reveal the PR fees, it forms part of an overall £12m process.
Eulogy will engage in national and regional activities, focusing on a series of events designed to 'celebrate the brand' and create PR and photo opportunities. There will also be a digital element.
Eulogy chief executive Adrian Brady said: 'We've got to market a significant rebrand by using great creative ideas to excite consumers and giving genuine stand-out stories to the media.' Eulogy will report to Santander UK head of corporate comms Anthony Frost.
Six agencies were invited to pitch, including The Red Consultancy and The Launch Group.
The pitch did not impact on Abbey's personal finance firm Citigate Dewe Rogerson, its corporate work with Brunswick, or its CSR work with The Red Consultancy.